In recent years, the trend of liberalization and globalization of economy has brought Vietnam economy both opportunities and challenges requiring the government and authorities put more efforts. In the field of Finance & Banking, we have built crucial basis for a financial monetary economy, technology modernization and bank operations to create the market mechanism. The institutions for bank operations have been improved and the operating mechanism of monetary policy has been innovated basically. Moreover, regulations and international standards of bank operations have been applied, so the credit quality has been improved significantly. However, in the period of integration, the opening of the financial market increases the number of wealthy foreign banks with high technology and management quality entering into Vietnam market, pressure of competition for commercial banks in Vietnam also increases along with the loosened regulations for foreign financial institutions. At that time, with the small size, low management quality, low technology and labor skills, the commercial banks will not catch up with foreign commercial banks and lose the game if they do not innovate. Besides, occurring risks of banks; especially the credit risks, have not been managed and controlled strictly, which can lead to a big loss. At the moment, the risk of bankruptcy of banks can appear at any time if they do not focus on enhancing the efficiency of risk management in their business activities. With the reasons above, ensuring the sustainability and consistency of the development is the most important target in management and operation of Vietnam commercial banks. One of necessary strategic solutions is to reorganize and upgrade the control system, internal audit of each commercial bank. In the small scope, among activities of bank, the credit activities need focusing on because it is the main source of finance for the banks, however, containing a lot of risks. Recognizing the importance of internal auditing of credit activities in the time working at Petrolimex, I choose the topic for the Master thesis: “Improving the internal credit audit system in Petrolimex Group Commercial joint stock Bank”