While empowering economic and social development, artificial intelligence (AI) is also reshaping the internal pay distribution structure within firms. Taking the establishment of the National New-Generation Artificial Intelligence Innovation and Development Pilot Zones as a quasi-natural experiment, based on a sample of Chinese A-share listed companies from 2015 to 2023, the impact of the pilot zones on intrafirm pay gaps and its underlying mechanisms was invetigated. The findings show that the establishment of the AI pilot zones significantly narrows intra-firm pay gaps, and this result remains robust after a series of robustness tests such as replacing the explained variable. Mechanism analysis indicates that the narrowing effect of the AI pilot zones on intra-firm pay gaps is likely achieved by lowering managerial risk compensation, curbing earnings management, and enhancing ordinary employees' bargaining power. Heterogeneity analysis reveals that, from the perspective of internal characteristics, the impact of the AI pilot zones on intra-firm pay gaps is more pronounced in small and medium-sized enterprises, nonstate-owned enterprises, and labor-intensive firms. From the perspective of external environment, this effect is more evident among firms located in eastern and western China, as well as those subject to weaker external audit oversight. Further analysis demonstrates that the reduction in intra-firm pay gaps is mainly reflected in the narrowing of excessive pay disparities. The conclusions provide empirical evidence for revealing the internal mechanism through which artificial intelligence affects intra-firm pay gaps, and also offer important references for achieving the goal of common prosperity in the digital economy era.