Traditional enterprises relying on platform enterprises to complete digital transformation are a good solution to the cold start dilemma. However, there are still problems such as an unclear transformation process, difficulty for traditional enterprises to eliminate their dependence on the platform, and difficulty in acquiring or complementary innovation in the early stage for the platform. Based on the case of Ding Talk helping ADOPT A COW to complete digital transformation, this paper analyzes the specific process of platform enterprises helping traditional enterprises complete digital transformation, explores how platforms can promote participants' innovation and obtain complementary innovation after participants' successful transformation from a bilateral perspective, and finally completes the mechanism of collaborative innovation. In the early stage of digital transformation, the platform helps traditional enterprises digitize their work processes through data empowerment. At this time, relying on innovation is the mainstay. After that, the platform helps traditional enterprises to complete the digitization of their business models, and traditional enterprises become embedded sub-platforms to provide complementary innovation; Traditional participations as players continue to cooperate with multiple platforms, and bilateral collaborative innovation will eventually transform into multilateral collaborative innovation.