Based on the resource-based view and social network theory, this paper constructs an analytical framework that integrates “resource support-resource allocation” and “innovation peer effect-competitive collusion effect” to investigate the impact of cross-owners on corporate R&D investment. Using a sample of A-share listed companies from 2007 to 2022, the findings reveal that the relationship between cross-owners and corporate R&D investment is inverted U-shaped. The moderation analysis indicates that redundant resources and market power weaken the inverted U-shaped relationship between cross-owners and corporate R&D investment, whereas digital transformation and operational efficiency strengthen this relationship. The heterogeneity analysis reveals that the inverted U-shaped relationship between cross-owners and corporate R&D investment is more pronounced in private enterprises and firms located in regions with higher levels of marketization, compared to state-owned enterprises and firms in regions with lower marketization levels.