Based on resource dependence theory and signal transmission theory, using manually collected corporate-customer pair data that are all listed companies, this paper systematically investigated the impact of customer earnings performance on corporate innovation investment. The results of the study found that the better the customer's earnings performance, the better the company's innovation investment. By examining the role of supply chain relationship and the degree of product diversification of supply chain companies on the adjustment of the relationship between the two, it is found that when the supply chain relationship is more stable and tends to be benign, the synergy effect of supply chain companies is more obvious, that is, high surplus customers have an effect on the company. The positive impact of innovation investment is stronger; when the degree of product diversification between the company and its customers is lower, the positive impact of customer earnings performance on the company's innovation investment is more significant. At the same time, it was discovered that high-profit customers promoted innovation investment by reducing business risks. Further research found that the higher the degree of corporate financing constraints, the higher the degree of market competition, and the stronger the relative bargaining power of customers, the positive impact of customer earnings performance on corporate innovation investment will increase significantly. The research conclusions expand the theoretical boundary of the economic consequences of customer earnings performance, and have important enlightenment significance for the promotion of supply chain integration and supply-side structural reforms.