With the acceleration of the process of global economic integration, the status of China's market economy has been continuously enhanced. In order to achieve long-term development in the unpredictable economic market, small and medium-sized enterprises (smes) should continuously strengthen the control and improvement of their internal systems to enhance their competitiveness and influence. Therefore, the development of internal audit is more and more concerned by enterprises. By giving full play to the evaluation, consultation and control role of internal audit, not only can the internal management system of enterprises be optimized, but also the risk factors existing in management decisions can be found to improve the management economic benefits of enterprises. However, the status quo of internal audit of many small and medium-sized enterprises in China has many problems, such as the imperfect standard system of internal audit, low professional quality of audit staff, lack of independence and so on. As a result, it is difficult for internal audit to actively promote the rapid economic development of small and medium-sized enterprises and establish and improve the internal control system. Therefore, small and medium-sized enterprises should improve relevant laws and regulations of internal audit, improve the comprehensive quality of internal auditors, enhance the independence of internal audit, and transform the audit function to respond