The exclusive dealing behavior of “pick one of two” on two-sided platforms has received widespread attention. It constructed a duopoly dynamic game model and considered the strategic response of competitors to the platform’s exclusive behavior. The result shows that when there is a significant horizontal differentiation between platforms and the service cost is low， there is an equilibrium that one platform implements exclusive dealing and the competitor platform chooses to actively respond. Furthermore， welfare analysis reveals that exclusive dealing leads to loss of consumer surplus and social efficiency， which implies that exclusive dealing strategy has the strong anti-competitive effect. The conclusions not only enrich the economic research about platforms’ abuse of market power， but also provide references to antitrust authorities in the future.