We start with the classic tradeoff theory and the irrationality of the top managers to explore the influence of overconfident CEOs to corporate capital structure. Instead of using corporate debt ratio, we try to measure the leverage with “overdebt” since the target leverage ratio differs among different enterprises. The empirical result shows that, the overconfidence of CEOs leads to overdebt. Moreover, we found that this phenomenon is much more significant at a company with lower financial constraints and a better capital environment. From the ownership structure perspective, we found that overconfident CEOs would deteriorate the leverage in a company with multiple large shareholders, due to the conspiracy behind those large shareholders. But for foreign shareholders, they are much more likely to supervise and restrict the overconfidence of CEOs. We enriched the content of capital structure and behavioral finance at some extent and showed policy implications to further advancing deleverage and achieve a soft landing.