Based on the sample of Chinese A-listed firms from 2003 to 2020, this paper investigates the effect of common institutional ownership on labor income share. The result shows that common institutional ownership can significantly increase firms’ labor income share. Mechanism tests indicate that common ownership can: 1) alleviate financial constraints by reducing the debt financing costs and increasing the trade credit financing, thus increasing the labor income share; 2) improve corporate innovation and therefore enhances the demand for highly-skilled labor, which eventually boost labor income share. Competitive hypothesis test represents that common institutional ownership can reduce the monopoly power of enterprises and decrease monopoly rent, so as to increase the proportion of labor in the distribution. Further analyses present that the network formed by the common ownership can effectively exert the financing support role of SOEs and the knowledge spillover effect of innovative-advantage firms, which contributes to the labor income share increasing of other related firms in the network connection. This study not only enriches the economic consequences of common institutional ownership, but also provides policy guidance for the government to further optimize the income-distribution pattern by deepening the reform of the financial market.