Enterprise innovation is an important practice way for enterprises to achieve sustainable development. Under the digital era, the artififi cial intelligence enterprises as a new organizational carrier, leads the continuous evolution and development of new economic forms in the future. How to improve the sustainable innovation ability of artificial intelligence enterprises has become an important research topic. Traditional studies have confifi rmed the impact of external formal institutions on the innovation capability of enterprises, ignoring the important role of social trust and traditional culture as an informal institution in driving enterprise innovation. Furthermore, based on China's A-share AI enterprises from 2010 to 2019, this paper empirically examines the impact of social trust on AI enterprise innovation, and examines the moderating effect of external formal institutions between social trust and AI enterprises innovation. The results show that social trust has a signififi cant positive effect on the innovation input and total factor productivity of AI enterprises, indicating that social trust as a social legitimacy mechanism can improve the innovation ability of AI enterprises, and the research conclusion still robust after considering the endogenous problem. Secondly, external formal institutions including marketization environment and Confucian culture have a negative moderating effect on the relationship between social trust and AI enterprises innovation, showing the substitution effect of institutional and social trust on the innovation of AI enterprises. The contribution of this paper is to enrich the research on the inflfl uencing factors of the innovation ability of AI enterprises in the age of digital intelligence, and provides experience for promoting the innovation of AI enterprises based on the view of institutions integration.