Answer： ICH GCP R2 5.19.3 The mentor should ensure that the auditing of clinical trials/systems is conducted in accordance with the mentor's written procedures on what to audit, how to audit, the frequency of audits, and the form and content of audit reports The sponsor of Article 52 of the 2020 GCP in China shall formulate an inspection plan and procedures based on the content of the materials submitted to the drug regulatory department, the number of subjects in the clinical trial, the type and complexity of the clinical trial, the risk level affecting the subjects, and other known related issues. A common working mode is for the applicant or contract research organization (CRO) to develop an annual audit plan at the company level, which includes all audit activities for the current year, including the type of audit plan, audit time, planned audit objects, planned audit projects, etc. CRO can also develop project audit plans for specific projects undertaken, which include audit types (such as research center audits, experimental master file audits), number of audits, planned audit times, and so on. In addition, an audit plan can also be developed for a specific audit, which includes the scope and sampling ratio of documents to be reviewed in this audit, interview personnel arrangement, on-site inspection objectives, and so on. Regardless of the audit plan, it is necessary to manage audit activities according to the company's specific management model and the company's audit SOP.