The essence of merger and acquisition is to combine the advantages of two enterprises together to conduct manpower resource integration, organization mission integration and organization culture integration. The purpose is to acquire the synergy of M & A. This research mainly investigates the relationship between the merger and acquisition and business performance in the banking industry and also about the moderating effect of cross culture management. As the result it is found that: (1) there is a positive relationship between the integration of merger and acquisition in the banking industry and its business performance; (2) "cross culture management" will generate a moderating effect on the integration of merger and acquisition in the banking industry and the business performance. (3) the person to be selected for the highest level management after the bank is merged and acquired is the general manager of the acquiring firm (first culture). Persons to be selected for heads of middle level and base level use "the third culture" management system which means executing the "management system of the acquiring firm or the company being acquire depending upon whichever is more advantages" to conduct.