Abstract: With the advent of the era of artificial intelligence, the industrial system and mode of production are transforming, which has an impact on the labor market and the distribution pattern of national income. Under the background, based on the panel data of micro enterprises, this paper studies the impact of AI on the labor share of income. The results with PSM-DID method show that AI can significantly increase the labor share of income by 1.4-1.7 percentage points on average, and the effects of AI on labor share of income show heterogeneity across ownerships, export status and between labor-intensive and capital-intensive industries. We also explore the mechanism behind the correlation between AI and labor share of income with causal mediation analysis (CMA) and find that the mechanism of AI to promote labor share of income is mainly labor promotion effect and TFP is a mediator which carries the influence of AI on the labor share of income for enterprises. The conclusion of this study has enlightenment significance for the reform of income distribution in the "artificial intelligence revolution" in China.