The purpose of this study is to explore the peer effect in innovation input in manufacturing enterprises from the perspective of Confucian culture, and to use the data of listed manufacturing companies in China from 2011 to 2020. The findings show that there is a peer effect in the innovation input of manufacturing enterprises. The influence of Confucian culture has a positive impact on the innovation input of manufacturing enterprises, and enhances the peer effect in innovation investment of manufacturing enterprises. Heterogeneity analysis reveals that non-state-owned enterprises and enterprises operating in areas with higher business environment index show more peer effects in manufacturing enterprises' innovation input, and the moderating effect of Confucian culture is more obvious. Further analysis shows that firm age, firm size, market competition and digital financial index and other factors affect the peer effect in innovation input in manufacturing enterprises. The innovation input of peer firms has a positive impact on the innovation output of focus firms by promoting the innovation input of focus firms, and these mechanisms are more effective under the influence of Confucian culture. The findings of this study reveal the importance of Confucian culture and peer effect in innovation input in manufacturing enterprises, and provide an important decision-making reference for enterprise managers.