The uncertainty of economic policy has a structural impact on the financing behavior and capital structure of enterprises. Based on the panel data of A-share listed companies from 2010 to 2019, this paper studies the impact path of economic policy uncertainty on the adjustment of enterprise capital structure. The results found that the uncertainty of economic policy hinders the convergence of corporate capital structure to the target value, and after controlling the regional development level, economic growth rate, province and corporate heterogeneity, the above conclusions are still valid. The uncertainty of economic policy mainly affects the adjustment of corporate capital structure through the change of the increase equity of debt rather than the decrease. Furthermore, the adjustment of enterprises above the capital structure target is more affected than those below the capital structure target; after the sample is divided into three groups of high, middle and low, the uncertainty of economic policy has a more significant impact on the middle and high groups. Although economic policy instability has increased the cost of capital adjustment for enterprises, it is conducive to restraining over investment and optimizing the capital structure of enterprises with surplus capital. Therefore, the adjustment of economic policies in the short term can optimize the capital structure of enterprises, but in the long run, capital marketization is still the main way to optimize the capital structure of enterprises.