Abstract: The behavior of the platform enterprises entering into the complementary markets and competing with complementary enterprise in the value capture link will generate significant impact on the innovation of platform enterprises. Taking Apple Inc. entering the application market by introducing the software of Clips into the photography and video market as a case, this paper employs the difference-in-difference model to examine the innovation response of the complementary enterprises after the entrance of the platform enterprises with the consideration of the impact of the scale heterogeneity of the complementary enterprises. The findings show that the platform enterprises’ entrance into the complementary market has stimulated the innovation of the complementary enterprises, and that compared with the small scale complementary enterprises, the large-scale complementary enterprises may adopt more active innovative strategies when faced with the entrance of the platform enterprises. In the short term, the platform enterprises entering the complementary markets may improve the efficiency of the platform ecosystem; however, this influence may not be significant in the long term, the platform enterprises can optimize the platform ecosystem by entering the complementary market.

Key words: platform enterprises, complementary market access, complementary enterprises’ innovation, DID model