Abstract: The deepening reform of the electricity spot market has brought new opportunities and challenges to the retailers. Research on decision-making of the retailer in the spot market is of great significance. The price-quota function is used to quantify the competition faced by the retailer. The paper establishes the cost and income model of electricity procurement and selling by a retailer, and generates a series of scenarios with different spot price based on lognormal distribution, and quantifies the risk in all scenarios with CVaR mode, and finally establishes the profit-risk objective function. In the case study, the paper compares the selling price, market share, the proportion of electricity procuring in the medium and long-term market, risk and profit of the retailer with and without the long and medium term trading restrictions under different risk preferences. The case study shows: when there is no restriction on medium and long term power procure, the retailer will set a higher retail price and sign a large number of medium and long term contracts; when there is a restriction on medium and long-term power purchase, the retailer must reduce the retail price to obtain more medium and long term trading qualifications to maximize the profit, and both the risk and profit of the retailer are lower than the level when there is no medium and long term restriction, and meanwhile the benefit of the demand sides increases.