Abstract: Under the sweep of the new wave of industrial technology revolution, digital productivity is driving the digital transformation of social production worldwide with unprecedented speed, breadth and depth. In this context, clarifying the profound impact of digital transformation on innovation activities and the underlying mechanism will undoubtedly be beneficial for promoting the development of China's digital economy and the construction and improvement of a data-driven innovation system. In view of this, The article views the construction of Big Data Pilot Zones as a quasi-natural experiment of regional digital transformation. A theoretical analysis framework for the impact of Big Data Pilot Zones construction on urban innovation level is constructed. Based on the panel data of 285 prefecture-level cities and listed companies in China from 2009 to 2019, we empirically tested the impact effects and mechanisms of action of the construction of Big Data Pilot Zone on urban innovation level using double difference method, triple difference method and moderated mediated effect model. It is found that the construction of Big Data Pilot Zones significantly promotes the improvement of urban innovation level, and this finding still holds after the robustness tests such as PSM-DID and instrumental variable method. The mechanism test shows that the construction of Big Data Pilot Zones promotes the improvement of urban innovation level by optimizing factor allocation efficiency, promoting industrial structure upgrading and enhancing entrepreneurial activity, and regional knowledge absorption capacity plays a moderating role to different degrees in the above paths. The heterogeneity test shows that the innovation promotion effect of the construction of the Big Data Pilot Zones is mainly reflected in private enterprises, while it has a negative impact on the innovation level of state-owned enterprises. The construction of the Big Data Pilot Zones promotes the quantity of innovation in low-digital-empowered industries and suppresses the quantity of innovation in high-digital-empowered industries while on the other hand, it improves the quality of innovation in high-digital-empowered industries and does not have a significant impact on the quality of innovation in low-digital-empowered industries. Our research provides important insights for deepening the construction of Big Data Pilot Zones for and implementing the innovation-driven development strategy. This paper contributes to the literature from the three perspectives.First, in terms of research content, this paper focuses on the digitalization impact of the construction of the Big Data Pilot Zones, and more comprehensively sorts out and evaluates the impact effect and mechanism of the construction of the Big Data Pilot Zones on urban innovation, so as to provide empirical evidence and theoretical guidance for promoting regional digitalization reform and the construction of the Big Data Pilot Zones. Secondly, this paper uses double difference, instrumental variables, triple difference, and moderated mediated effect models to quantitatively assess the impact and mechanism of the construction of Big Data Pilot Zones, which effectively alleviates the endogeneity problem in the process of model estimation. Third, in terms of research perspective, this paper measures the innovation level from both "quality" and "quantity" dimensions, and assesses the innovation effect of the construction of the Big Data Pilot Zones at the city level, while using micro-enterprise data to re-validate and enrich the empirical results, deepening the interpretation of the positive effect of the construction of the Big Data Pilot Zones.