Abstract: In order to improve market performance of new platforms’ preannouncement, the paper explores the problem on preannouncement strategies based on two-sided market and constructs formal strategy(F)and informal strategy(I)of new platform. By constructing a duopoly model with symmetrical product preannouncement strategies F-F, I-I and asymmetric F-I, the article analyses impacts of consumers and develops single-homing, consumers and develops multi-homing and consumers multi-homing and developers single-homing to platform competition. The result shows that while both of platforms adopt strategy F, if consumers and developers single-homing or consumers multi-homing and developers single-homing, a promoting on service level or a receding on cross-group network externalities can be beneficial to profit of platforms, if consumers and developers multi-homing, an enhancing on service level or cross-group network externalities can be beneficial to profit of platforms, while both of platforms adopt strategy I, the platform owning a larger installed base of developers gains more profit. In addition, whatever the homing consumers choose and whatever the strategy developers choose, strategy I always appears as the dominant strategy to both of platforms.

Key words: platform enterprise, two-side market, Hotelling model, preannouncement strategy, multi-homing