Open innovation is an important approach for manufacturing enterprises to achieve high-quality development.Based on micro-level data from manufacturing firms listed on the Shanghai and Shenzhen A-share markets, this study treated the pilot program for the construction of the social credit standard system as a quasi-natural experiment and employed a multi-period difference-in-differences (DID) approach for empirical analysis.The findings revealed that the construction of the social credit standard system enhances open innovation levels in manufacturing enterprises in terms of both behavior and performance.This conclusion remains robust after a series of sensitivity tests.Mechanism analysis shows that social credit construction reduces the risks associated with innovation activities and increases firms' willingness to engage in collaborative R&D, thereby improving open innovation levels.The social credit system construction mainly promotes strategic innovation behaviors and performance, while its effect on substantive innovation performance is not significant.The promotion effect is particularly evident in state-owned enterprises, small enterprises, and firms with strong internal controls.In industries characterized by high competition and where technology is more prone to infringement, the positive impact of social credit construction on open innovation is more pronounced.This study will provide policy implications for improving the social credit standard system and promote the level of open innovation in enterprises.