1. Audit is to collect and analyze evidence of data to evaluate the financial situation of enterprises, and then draw conclusions and reports on the correlation between data and accepted standards. Auditors must be independent and have relevant professional knowledge. Second, the purpose of the audit is: 1, the implementation of accounting supervision, in addition to evaluation and notarization. Audit supervision includes not only checking accounting accounts, but also field investigation, investigation, analysis and inspection of calculation behavior and all economic activities, which means auditing and checking calculation; 2, the implementation of inspection and audit is independent of the accounting part of the full-time supervision and inspection; The purpose of accounting check is to ensure the authenticity and accuracy of accounting data, and the scope, depth and methods of inspection are limited, while the purpose of audit is to confirm the truthfulness, legality and efficiency of financial revenue and expenditure. Auditing and checking accounting information is only one of the means to achieve the purpose of auditing, but it is not the only means. 3. Provide necessary data and information for management and decision-making; The audit method system consists of planning method, implementation method and management method. The implementation methods are mainly to determine audit items, collect audit evidence, evaluate against standards, put forward audit reports and decisions, and use data inspection, physical inspection, audit investigation, audit analysis and audit sampling. Its purpose is to complete the audit task.