Abstract: In this paper, basing on the panel data fixed effect model, using the operating data of large thermal power listing Corporation, studies the influence of “separation of plant and grid” policy on the performance of these thermal power listing Corporations. The results show that, although “separation of plant and grid” make these thermal power listing Corporations income has increased significantly, but had no a significant impact on profits, and regulation during these Corporations profits and sometimes negative. In addition, the main business cost changed income in the same direction, but the profit change in the reverse direction. Price index of electricity and fixed assets, change in income and profit changes in the same direction, whiles price index of coal changes caused by changes in income and profit of reverse direction. The number of employees had no significant impact on the income and profit of these thermal power listing Corporations.