Taking the uncertainty index of policy and the experience data of A-share listed companies in China from 2007 to 2016, this paper makes an empirical study on the relationship between policy uncertainty and capital structure decision-making. The study finds that when lagging policy uncertainties increase, the asset-liability ratio of the enterprise will decrease on average, and the policy uncertainty is negatively correlated with the long-term and short-term asset -liability ratio. State-owned property rights help to mitigate the negative impact of policy uncertainty on capital structure. In addition，the impact of policy uncertainty on corporate asset-liability ratio is even more pronounced for enterprises in areas with high marketization degree. Furthermore, such policy uncertainty will significantly slow down firm，s adjustments toward their optimal capital structure.