With the continuous development of market economy and the increasing prosperity of capital market in our country, accounting firms are taking on more and more important responsibilities as "gatekeepers" of capital market. Audit quality, as the core of accounting firm management, directly affects the stability and development of the financial market. The level of audit quality is directly related to investors' trust and dependence on financial reports, the reputation and business development of accounting firms, and influences corporate governance, financial market stability and government supervision. All along, the regulatory authorities pay more attention to the audit quality management of the firm. In the announcement disclosed by the China Securities Regulatory Commission, the firm will be punished for illegal behaviors every year. In recent years, the Ministry of Finance and the China Annotations Association will conduct practice quality supervision and inspection of the firm every year, the audit quality management of the firm still has defects. These problems may cause a crisis of trust in the public, which in turn affects the development of the entire industry. However, the current accounting firms do not pay enough attention to the audit quality management and the supervision is insufficient, and the audit quality becomes low. In order to promote the high-quality and sustainable development of the registered accounting industry, it is urgent to strengthen the audit quality management of accounting firms. Therefore, this paper takes M Accounting Firm as the case study object, analyzes and summarizes the existing problems in audit quality management of accounting firms found during the internship, finds out the causes of the problems, and puts forward targeted optimization suggestions, so as to strengthen the audit quality management of this accounting firm and promote its healthy and sustainable development.