For the uncertainty of consumer demand, price-postponement is considered to be an effect measure to cope with demand fluctuation and facilitate market clearing. Based on the two-echelon supply chain consisting of a supplier and a retailer, the optimal retail price is proposed, then the retailer profit function of the decentralized supply chain and the supply chain profit function model of the centralized supply chain are established, respectively. The existence and uniqueness of order quantity are proved by unimodality conditions, and optimal solutions are obtained. Comparative and numerical analysis show that, using price-postponement can significantly increase the gross profit of the decentralized supply chain compared to the fixed price, although the income is lower than that of the centralized supply chain.