The article builds a competitive model of the incumbent and later entrant, considering the case of single-homing andmultihoming. Results show that the conditions that later entrant platform profits exceed incumbent platform are the same underthe case of single homing and multihoming. At the same time, the later entrant should turn to charge rather than subsidizingenterprise when two platforms get an equilibrium. Later entrant platform can focus on improving user's evaluation of one sideif it wants to exceed the incumbent in profits. Finally, the case of Tmall and Amazon China in B2C market is discussed.