As for the relationship between equity incentive and corporate performance, this paper studies from the perspective of methodology. It is proposed that the correct understanding and use of the method of dealing with endogeneity is the premise of the accurate evaluation of equity incentive effect. In view of the fact that the traditional PSM cannot achieve the matching of unobservable factors and the sample-selection bias still exists partially, this paper uses the improved PSM+DID to find that, first, equity incentives improve ROE and ROA, with a margin of increase of 22.22% and 19.51% respectively; second, from a dynamic point of view, with the passage of the year, the performance of the company gradually slowed down, and equity incentive showed a diminishing marginal effect. By comparing the results of PSM+DID and traditional PSM evaluation, this paper proves that PSM does overestimate equity incentive effect, and PSM+DID's evaluation results are more accurate and robust. In addition, this paper also confirms that the macroeconomic situation does not affect the effect of equity incentive.