In order to accelerate the reform of China’s banking sector，China government has taken an array of measures since 2003，including carve-outs of non-performing loans，reconstruction，introduction of the overseas strategic investors，and public listings． This paper employs DEA approach to estimate and compare the efficiencies of 32 commercial banks during the period 2002-2008． The results indicate that，although the overall efficiency of China’s banking sector increased significantly after the several-year’s reform，large stateowned banks were still the least efficient． The reconstruction of the large state-owned banks could not reduce the gap of efficiency between the state-owned banks and the joint-stock banks as well as the city commercial banks，but the behavior of carve-outs of non-performing loans from the large state-owned banks brings forth higher technology efficiency． Furthermore，the overseas strategic investors encouraged by the government can help Chinese banks to improve their allocate efficiency． In summary，the reform of China’s banking sector has both positive and significant impacts on the improvement in the overall cost efficiency of Chinese banks．