At present，the implementation of direct power purchase by large consumers allows the consumers to choose freely and also motivates the generators to take proper price-making strategy for the contract with large consumers on the power purchase.With demand uncertainty，the pricing strategy of the generator will affect the order of power purchasers.A coordination mechanism of electricity supply chain based on the cooperative game is proposed to make the buyer and seller undertake the risk of quantity deviation between the actual demand and contract quantity together.Moreover，the pricing strategy which is made to maximize profits of the supply chain can stimulate power purchasers to take the initiative in choosing purchase strategies which benefit the generators，and also increase the benefit of trade.Simulation results show that the model proposed is practical and feasible，and that it can achieve Pareto optimality in an electricity market.