Retailers are puzzled by customer returns all along the time. As e-commerce develops rapidly, customers can't observe the product in the online shops and it results in more returns. In the omni-channel environment, offline showrooms are adopted to attract more customers to the offline stores. We think showrooms can help the store have more customers and we prove it with our models. Then we think this's a way to reduce returns in certain conditions. Our results can be expressed: 1) when the offline operating cost isn't so large or the return cost is large, the retailer can gain more profit by providing a showroom; 2) showrooms decrease the retailer's profit when the offline operating cost is large or the return cost isn't so large. Therefore, retailers should consider all related factors to decide whether to provide an offline showroom.