Abstract: In recent years, China's technological innovation strength has made significant progress, but it still faces problems such as weak basic research and original innovation capabilities, lack of key core technologies, and disconnection between innovation and industry. The reasons for these problems are complex, and the insufficient development of technology intermediaries may be one of the important reasons. Technology intermediaries play an important role in urban innovation and development. The National Technology Transfer Regional Center (NTTC) is a high-level technology intermediary and an important component of the national technology innovation system. As of August 2023, China has built 12 NTTCs, and the construction effectiveness of these NTTCs has always been a concern. Based on the panel data of 278 prefecture-level and above cities in China from 2010 to 2021, this paper uses the staggered difference-in-difference model to conduct an in-depth examination of the causal relationship and key mechanisms between technology intermediaries represented by NTTC and urban innovation. The results show that NTTC significantly promotes the improvement of general and core technological innovation levels in the city, but more importantly, it promotes the improvement of general technological innovation levels in the city. The government support effect, innovation factor inflow effect, and enterprise agglomeration effect are the key mechanisms of NTTC promoting the improvement of urban innovation level. NTTC has a spatial spillover effect of “∽” type on the innovation level of surrounding cities, which can promote the improvement of innovation level in cities within suitable distances, but has no significant impact on cities in closer or farther distances. The regional characteristics and administrative levels of a city can lead to differences in the improvement effect of NTTC on the level of urban innovation. This paper has the following policy implications. First, the government should continue to strongly support the construction of NTTC, actively promote the construction of various types of technology intermediaries while ensuring the quality of existing NTTC construction. Second, the government should strengthen policy support, optimize the foreign investment and business environment, fully amplify the government support effect, innovation factor inflow effect, and enterprise agglomeration effect of NTTC establishment, and assist urban innovation and development. Third, the government should implement a differentiated technology intermediary construction strategy, making technology intermediaries an important support for bridging the regional innovation gap. This paper may have the following marginal contributions: (1) Distinguishing from the existing literature on technology intermediaries, this paper focuses on technology intermediaries represented by NTTC and urban innovation, emphasizing the causal relationship between the two to enrich the existing research.(2) In addition to testing the policy effect of NTTC, this paper also discusses the key mechanism of NTTC on urban innovation level from theoretical and empirical analysis, which helps to clarify the internal logic of technology intermediary affecting urban innovation.(3) The conclusion of this paper may have reference value for the government to optimize the construction of technology intermediaries, and it is also of great significance to improve the national technology innovation system and accelerate the realization of self-reliance science and technology.

摘要： 科技中介对于城市创新具有重要作用。国家技术转移区域中心（NTTC）是高级别的科技中介，也是国家科技创新体系的重要组成部分，其建设成效一直备受关注。本文利用双重差分模型深入分析了以NTTC为代表的科技中介对城市创新水平的关键作用和内在机制。研究发现：NTTC显著促进了所在城市的一般技术和核心技术创新水平提升，但更多的是促进了城市一般技术创新水平的提升。政府支持效应、创新要素流入效应和企业集聚效应是NTTC促进城市创新水平提升的影响机制。NTTC对周边城市的创新水平存在“∽”型的空间溢出效应，即能够促进周边适宜距离内的城市创新水平提升，对距离较近或较远的城市影响不显著。城市的区域特征和行政级别会使NTTC对城市创新水平的提升效应产生差异性。本文的研究结论可能对于政府部门优化科技中介建设具有参考价值，同时也对完善国家科技创新体系，加快实现科技自立自强具有重要意义。