Evolutionary game theroy that links game theory with dynamic evolution is the frontier theory in the economic field. This paper uses the evolutionary game theroy to analyse the two different bid rules,and analyses the generator’s price strategies in the process of bidding in a power market. It points out that it should be settled according to the market clearing price when supply tensely and according to pay-as-bidding price when supply abundant, which could not only adjust the market clearing price, but also make generators adopt suitable bid price strategies.