Increasing the share of labor income in enterprises is an important pathway to achieve common prosperity and enhance public well-being. The formation of the labor income share is not only determined by internal profit distribution decisions and the structure of factor markets within enterprises but also is profoundly influenced by the macro-institutional environment. From the perspective of the theory of factor income distribution, the division of capital and labor income is affected not only by technological progress and the degree of capital substitution but also by constraints, such as corporate financing conditions, operational stability, and the level of human capital investment. In this particular context, government procurement, as a key fiscal expenditure tool, may alter the pattern of labor income distribution in enterprises by improving the external environment, enhancing operational expectations, and guiding changes in employment structure. Based on this, this study selects Chinese A-share listed companies from 2015 to 2022 as the sample and systematically analyzes the impact of government procurement on the labor income share of enterprises and the underlying mechanisms. The study finds that government procurement can significantly increase the labor income share of enterprises. Mechanism tests indicate that government procurement primarily exerts its effects through three channels: first, alleviating financing difficulties, as government procurement contracts serve as a "credit label" to enhance corporate credit; second, maintaining operational continuity, as stable government procurement demand can reduce the risk of performance fluctuations; third, promoting the optimization and upgrading of human capital structure, since the high requirements of procurement projects drive enterprises to invest more in skilled labor. Heterogeneity analysis shows that in regions with higher economic uncertainty, for enterprises with weaker internal controls, or for those with lower ESG ratings, the positive effect of government procurement is more pronounced. This research expands the boundaries of the study on the microeconomic consequences of government procurement, revealing a new mechanism by which government procurement boosts the labor income share and optimizes internal income distribution within enterprises. It provides empirical evidence and policy guidance for realizing the goals of common prosperity and high-quality development. The design of the government procurement system should be further optimized, with increased "targeted support" to guide enterprises to adjust their compensation distribution systems, achieving coordination between economic efficiency and social equity.