ROE is one of the important indexes of the commercial bank business efficiency. In order to study the commercial bank business efficiency and its impacting factors, we analyze the ROE index of the commercial bank by applying the analytical approach of Du Pont. On the basis of the comparative analysis of the commercial bank business status quo, we find out that capital management efficiency and the system of the state financial management are the key factors that create the difference of the capital business efficiency of the state commercial banks. Therefore the evaluation of the business efficiency of the modern commercial bank in the equal situations mainly depends on business efficiency.