I have worked in China National Intellectual Property Administration for 23 years, and have been engaged in patent literature research, patent information computer retrieval service, online retrieval technology research, patent database deep processing research and development, etc. In the early 1990s, as a visiting scholar, he conducted a one-and-a-half-year research on national online retrieval technology and information processing technology in the United States with the support of China Western Science Exchange Foundation Han.

Liu Yanhuai participated in and organized the research and development of National Natural Science Foundation projects, key research projects of the Ministry of Science and Technology, high-tech achievements application projects of the National Development and Reform Commission, major patent information technology projects of China National Intellectual Property Administration during the Tenth Five-Year Plan, 863 plan of the Ministry of Science and Technology, major special projects of the Ministry of Science and Technology, and was hired as an expert of the national intellectual property strategy formulation expert group and an expert of the 863 project expert database of the Ministry of Science and Technology.

Since August 2004, he has served as the president of Beijing Dongfang Lingdun Technology Co., Ltd. In August 2004, under the leadership of Liu Yanhuai, Beijing Dongfang Lingdun Technology Co., Ltd. undertook and completed the research and development tasks of two sub-projects of the 863 Program of the Ministry of Science and Technology-China innovative drug patent database with complex retrieval function-national family structure drawing and indexing system; The unique coding system of traditional Chinese medicine. In 2004-2005, it undertook and completed the research and development of the "Patent Literature Retrieval Service Application Demonstration Platform", a major project of the Ministry of Science and Technology. The project includes: a multi-database online retrieval platform with powerful professional retrieval function, two deep-processing Chinese and English bilingual world traditional medicine patent databases, and a deep-processing index world silicon material patent database. The above two achievements are independent intellectual property rights, reaching the international advanced level. In 2006, he undertook the special goal-oriented project of the 863 Program of the Ministry of Science and Technology. These works have made a useful exploration for establishing the national patent information basic platform in the future.