The low rate of technology transfer and the disconnect between industry, academia, and research supply and demand are structural bottlenecks currently hindering the in-depth advancement of China's innovation-driven development strategy. How to unclog technology transfer channels and activate collaborative innovation among enterprises through institutional innovation in technology market intermediaries is a core issue facing both theoretical research and policy practice. The establishment of the National Technology Transfer Center is an important institutional arrangement for the government to build a professional technology market intermediary system and address the disconnect between supply and demand of scientific and technological achievements. A-share listed companies from 2010 to 2022 were employed as the research sample. Based on a quasi-natural experiment of the establishment of the National Technology Transfer Center, the difference-in-differences method was adopted to identify the impact and mechanism of technology market intermediaries on enterprise collaborative innovation. It is found that the establishment of the National Technology Transfer Center significantly promotes enterprise collaborative innovation, a conclusion that remains valid after a series of robustness tests. Mechanism tests reveal that the National Technology Transfer Center effectively functions as a technology market intermediary, exerting a positive impact on enterprise collaborative innovation through two channels: promoting knowledge spillovers and driving resource integration. Further analysis indicates that the aforementioned facilitation effects are more pronounced in regions with more developed technology markets, in enterprises with stronger basic R&D capabilities, and in regions with greater technology resource mobility, revealing a three-pronged collaborative innovation promotion logic of "transferring out-receiving-smooth circulation". These findings provide incremental evidence for local governments to further improve the technology market intermediary system and promote the transformation of scientific and technological achievements, and bear important practical implications for optimizing the efficiency of innovation resource allocation and activating the vitality of collaborative innovation among enterprises.