Abstract: As the competition in the electronic retail market intensifies, online retailers have recently started to provide platform for manufacturers to allow they direct sell product to end consumers while charging a fee. We build a decentralized supply chain consists of two competing online retailers and one manufacturer where retailers are the leaders. Through a two-stage Stackelberg model, the effects of the four kinds of charging strategies of the two competing retailers on the optimal decisions and the performance of each channel member and the whole chain is analyzed. When competing online retailers adopt a no-difference charging strategy, the results show that proportional fee is more efficient than per-transaction fee from the stand of online retailers and the whole chain and leads to a lower retail price; however, the manufacturer prefers to charge per-transaction fee. When competing online retailers adopt a differential charging strategy, the online retailer sets the lowest charging amount and charging proportion according to the sales volume. It is more important that under two-part tariff when lump-sum fees greater than a certain threshold and smaller than a certain threshold can achieve Pareto-improving。Beside, this paper follows out applied investigations on the platform charging strategies for online retailers in the presence of horizontal competition in China.