Social commerce has grown in appearance, but profitability is deteriorating due to persistent competition. The service coupon, which is the main product of social commerce, is a structure of customers' pre-sale and post-service use. In this study, we examined the factors affecting perceived risk in three aspects; discount rate, coupon validity period, and time pressure in social commerce. As a result, the consumer’s perceived risk of purchase was increased with higher discount rates, shorter coupon validity period, and higher time pressure. The higher in perceived risk of the consumers has low intention of the purchasing in social commerce. Based on these empirical results, we suggested implications for service coupon marketing of social commerce.