Abstract:Based on the data from the main board listed companies from 2007 to 2016, the influence of the uncertainty of economic policies on the R&D investment of enterprises was investigated. Through the establishment of a nonlinear fixed-effects model, it is found that: (1) The influence of policy uncertainty on R&D investment has an inverted “U” type, that is, policy uncertainty is an incentive effect within a certain range; if it is too large, R&D is inhibited; ( 2) Regulatory effects show that equity concentration and equity checks positively regulate the impact of policy uncertainty on R&D investment; (3) Further research finds that the optimal shareholding structure is the top 5 equity concentration, second and third largest shareholder pairs. The major influence of the superposition of a large shareholder on the positive effect of the superposition is greatest.