Abstract: In a deregulated electricity market,the competitions of bilateral contract transacting include the competition between generation companies and large consumers and the contract price competition among multiple generation companies to get more power generation.To formulate these competitions,a master-slave game model for multiple generation companies and large consumers is proposed for the bilateral contract transactions.In this model,the goal of the generation company is to determine the optimal bidding price through the in-cooperative game with other power suppliers to maximize its bilateral trading profit;while large consumers decide their personnel purchase strategy to minimize their cost and based on the contract price provided by generation companies and the forecast of the spot price.Moreover,the existence proof and solution of the Nash equilibrium for the game model are presented.Finally,a numerical example is illustrated and the results show that each participant can benefit from the proposed game.