<p>The technology service platform (TSP) holds immense potential for optimizing technology services and driving a new wave of industrial transformation. The sustainable development of TSP requires a deep understanding of the collaborative dynamics among stakeholders and the factors shaping their strategies. Few studies have addressed the critical influencing factors of openness degree and entry—both of which are key in practice. This paper aims to bridge this gap and offer insights for the sustainable development of TSP. A tripartite evolutionary game model of owners, complementors and government is constructed. We explore the effects of various factors, including the admission fee, incremental benefit of owners and complementors, and potential loss, and government subsidies. Furthermore, the equilibrium solutions are derived, and the numerical simulation is investigated. This study demonstrates that: (1) The probability of the platform owners choosing high openness and complementors adopting entry strategy increases as the differences of incremental benefits between owners with different strategies and complementors with different strategies increase. (2) The higher differences of admission fee between high and low openness increase the likelihood of platform owners choosing high openness and complementors adopting entry strategy. (3) The results show that subsidy amount and coefficient to owners and complementors above a certain threshold will discourage government to implement subsidy policy. Government should adopt the moderate not over-high level of subsidy. Besides the direct financial support, subsidies also have indirect support. Subsidies can enhance the incremental benefit of owners and complementors. These insights provide practical recommendations for stakeholders, enabling them to design more effective strategies to foster the growth of the TSP.</p>