Abstract: In the urgent period of vigorously advocating independent innovation to promote the whole country’s self-reliance and self-improvement in national science and technology, the emerging phenomenon of large enterprises and their platform networks inhibiting independent innovation of small and medium-sized enterprises should be brought to more attention from researchers and government officals in China. In order to analyze whether the action space and freedom of platform network dominated by large-sized enterprises affect the innovation behaviors of its members, especially small and medium-sized enterprises that could be seen as latecomers or newcomers, this study focuses on the impact of autonomy of members in this sort of network on their own business model innovation. With collecting questionnaire survey data including 356 enterprises in China, empirical analyses have been conducted to test the proposed hypotheses and theoretical model in this research. The results show that: In a platform network dominated by large-sized enterprises, ①members’ autonomy is significantly and positively related to their business model innovation; ② the ambidexterity of members’ knowledge governance structure mediates the positive relationship between their autonomy and business model innovation; ③environmental uncertainty negatively moderates the direct relationship between member’s autonomy and business model innovation; ④specifically, environmental uncertainty negatively moderates the indirect effects of members’ autonomy on their business model innovation via the ambidexterity of knowledge governance structure. This study can reveal network autonomy as one of significant situational?factors that affect network innovation. Meanwhile, it can provide a new perspective for the relative researches and practices about governance space optimization of innovation collaboration networks that consist of relationships between large enterprises and small and medium-sized enterprises.