The two dimensions of supply chain concentration, that is, supplier concentration and customer concentration, have different effects on R & D input intensity of enterprises. Customer concentration can significantly promote R & D input intensity, while supplier concentration has a negative impact on R & D input intensity. Furthermore, considering the existence of enterprises with different property rights in our country, the promotion effect of customer concentration on R & D investment intensity is more obvious in non-state-owned enterprises, and the negative effect of supplier concentration on R & D investment intensity is alleviated to some extent. This study discusses the factors influencing R & D investment intensity from the perspective of enterprise supply chain, and re-understands the influence of supply chain concentration on R & D investment intensity. The conclusion has theoretical and practical significance on how enterprises view supply chain concentration and how to evaluate the impact of supply chain concentration on R & D activities.