Given that efficient energy dispatching has been promoted in electric power systems， this paper presents a strategy that independent power producers（IPPs） and the grid company can cooperate to apply efficient energy dispatching rules in day-ahead bidding market based on the analysis of their operating incentives. Using the profit models of different market agents， the solution of bidding process is provided and then is graphically modeled to analyze the impact of IPPs' bidding strategy in the bidding process. Efficient energy dispatching rules are applied to derive the cooperation mode and condition between IPPs and the grid company. The optimal cooperation strategy is derived and the corresponding profit allocation method is designed as well. An illustrative example is given to show the validity of this cooperation strategy.