DEA (Data Exchange Agreement) is used to make empirical study on the merger and acquisition performances of 46 China energy enterprises that happened from 2006 to 2012. The conclusions are listed as follow. Firstly, overall performances have a tendency of slow improvement, which is followed by a decline and then a remarkable enhancement. Secondly, sample performances of stock acquisition, which have a slow improvement, appear to be better than those of asset acquisition. Thirdly, during the first year after the acquisition, the performance of related party M&A is clearly better than that of unrelated party M&A. The performance of stock acquisition is unsteady while that of asset acquisition is steady and slow. And the performances of both stock acquisition and asset acquisition are basically the same. Fourthly, horizontal M&A show better performances than conglomerate M&A.