Based on the assumptions that the sales of new product are divided into two periods(the first period is the advance selling period, the second period is selling season period or spot selling period) and that the consumers have uncertain evaluation on product, this paper makes a research on the retailer’s return policy under the condition of uncertain demand and focuses on which returns policy can become the retailer’s optimal returns policy between no returns policy and providing returns policy for the pre-sale products. The results show that if the consumer is less likely to overestimate the product in the advance selling period, no returns policy and providing returns policy are equivalent, and both are the retailer’s optimal returns policy. Otherwise, no returns policy is the retailer’s optimal returns policy.