Manufacturing Execution Management System (MES) is the link of enterprise CIMS information integration and the basic technical means to implement enterprise agile manufacturing strategy and realize agile workshop production. This paper introduces the concept and functional model of MES, and the relationship between MES and ERP and field automation system, and describes the typical structure of MES system. Manufacturing industry is an important pillar industry of China's national economy and occupies a core position in the secondary industry. With China's entry into WTO and economic globalization, China is becoming the center of world manufacturing. China manufacturing enterprises are facing increasingly fierce competition at home and abroad. How to quickly improve the core competitiveness of enterprises is very important, that is, to promote industrialization by informationization, accelerate the process of informationization, take a new road to industrialization, and realize the leap-forward development of the productive forces of the whole society. Looking at the application status of manufacturing information system in China, the construction focuses on two aspects: ERP management system and workshop control system (SFC). However, in the past two decades, product marketing has rapidly evolved from production-oriented to market-oriented and competition-oriented, which also poses challenges to the management and organization of production sites in manufacturing enterprises. It is often impossible to cope with this new situation only by relying on ERP and field automation system. Manufacturing Execution System (MES) can just fill this gap. MES is a workshop-oriented production management technology and real-time information system that has developed rapidly in the world in recent 10 years. MES can provide users with a quick response, flexible and fine manufacturing environment, and help enterprises reduce costs, deliver goods on time, improve product quality and improve service quality. IT is suitable for different industries (household appliances, automobiles, semiconductors, communications, IT, medicine), and can provide good enterprise information management for single mass production and mixed manufacturing enterprises with both small and large-scale production of multiple varieties. At present, the application of MES system by well-known foreign enterprises has become a common phenomenon, and many domestic enterprises have gradually begun to adopt this technology to enhance their core competitiveness. Back to the information "fault" between enterprise planning layer and process control layer, the traditional production process adopted by China manufacturing industry for many years is characterized by "top-down" production as planned. Simply put, it is from the planning level to the production control level: enterprises make production plans according to orders or markets, and the production plans arrive at the production site, organize production and deliver products. The focus of enterprise management informatization construction is also mostly at the planning level, with production planning management and general affairs handling. For example, ERP is located in the upper planning layer of an enterprise, which is used to integrate the existing production resources of the enterprise and prepare the production plan. In the lower production control layer, enterprises mainly use automatic production equipment, automatic testing instruments, automatic logistics handling and storage equipment to solve the production bottleneck of specific production (process) and realize automatic control of production site. Due to the change of market environment and the continuous updating of modern production management concepts, the key to the benign operation of manufacturing enterprises is to make the "plan" and "production" closely cooperate, so that enterprises and workshop managers can grasp the changes in the production site in the shortest time, make accurate judgments and take quick countermeasures to ensure that the production plan is revised reasonably and quickly. Although ERP and field automation system have developed to a very mature level, because the service object of ERP system is the upper level of enterprise management, it generally does not provide direct and detailed support for workshop-level management process. The function of field automation system is mainly to monitor the field equipment and process parameters, which can provide field detection and statistical data for managers, but it is not a real management system. Therefore, there is a "fault" in management information between ERP system and field automation system, and they often appear powerless or weak in function for the scheduling and management needs of users at the workshop level. For example, in the face of the following typical problems in workshop management, it is difficult for them to give a perfect solution: when a user complains about a product, can you trace back all the production process information of the batch of products according to the product number? Can you immediately find out its raw material supplier, operating machine, operator, process, production date and key process parameters? ? When multiple types of products need to be mixed and assembled in the same production line, can the operation prompts be automatically checked and verified to prevent workers from assembly errors, product production process errors, product mixing and goods handover errors? ? What are the five most common product defects on the production line in the past 12 hours? What is the number of defective products? ? At present, what is the quantity of each product in the warehouse and the pre-process, middle-process and post-process lines? Which suppliers do you want to supply separately? When can you deliver the goods in time? ? How much time is the production line and processing equipment in production, and how much time is it stopped and idling? The main reasons that affect the production potential of equipment are: equipment failure? Scheduling error? Material supply is not timely? Inadequate training of workers? Or is the process index unreasonable? ? Can the quality inspection data of products be automatically counted and analyzed, and the random fluctuation and abnormal fluctuation of product quality can be accurately distinguished, so as to eliminate quality hidden dangers in the bud? ? Can you cancel the manual report and automatically count the production quantity, qualified rate and defect code of each process? The positioning of MES is the executive layer between the planning layer and the field automation system, which is mainly responsible for workshop production management and scheduling execution. A well-designed MES system can integrate production scheduling, product tracking, quality control, equipment failure analysis, network reporting and other management functions. On a unified platform, using a unified database and connecting through the network, it can provide workshop management information services for production departments, quality inspection departments, technical departments and logistics departments at the same time. By emphasizing the overall optimization of manufacturing process, the system helps enterprises to implement complete closed-loop production and establish an integrated and real-time ERP/MES/SFC information system.