1, different definitions: internal audit is a kind of assurance and consulting activity and an internal management function of an organization; External audit is a visa activity provided by an independent external institution.

2. Different objectives: the purpose of internal audit is to add value to the organization and improve its operational efficiency (management purpose); External audit is to provide a reasonable guarantee for the legitimacy, fairness and consistency of the organization's financial information.

3. Different scope of work: the scope of internal audit covers all aspects of enterprise processes, including risk management, control and governance processes, while external audit only focuses on enterprise financial processes and internal controls related to financial information.

4. Different methods: There are various methods of internal audit. According to the definition of IIA, internal audit should adopt "systematic and standardized methods", that is, different methods should be adopted in combination with the specific situation of the organization, which may also include some procedures of external audit, provided that the methods are "systematic and standardized". The methods of external audit are just some procedures of report audit.

5. Different customers: the ultimate customer of internal audit is the board of directors, which is the extension and concretization of the management function of the board of directors; The service object of external audit is all relevant stakeholders.