The electricity industry restructuring with the purpose of establishing competitive power market sweeps the whole world and affects various countries. Currently some several dozens of electricity markets have been created and in operation around the world. In China, succeeding to pilot operation for Northeast China and East-China power markets, the competitive power market will be built throughout the country. The power generators, as the main participants of the market, their benefits are mainly decided by what bidding strategies they employ. In contrast with thermal generation, bidding strategy for hydropower generators are much more complicated, because except the factor of cost, power price and market rules hydropower generations are also affected by various other factors such as natural water inflows, reservoir's regulation performance, overall water utilization requirements, hydrological and electric relations between reservoirs in the upper and lower reaches, and economic benefit relationship among different investment bodies of the plants etc.. In addition, almost all existing documents on electricity competition strategies show that researches have been done mainly on bidding strategies for thermal power generators, and for hydropower generators very few work have been done and there are no systematic studies. Therefore, against the situation that more and more hydropower generators'joining in the competitive electricity market,