This study uses the data of the listed companies from the Taiwan Economic News from 2008 to 2015, through the enterprise credit rating as a tool variable for two-stage minimum method to avoid endogenous problems, found that the directors and supervisors equity pledge on the cash effective tax rate has negative Influence, that is, corporate directors and supervisors who pledge equity will lead to serious agency problem between managers and shareholders, and the agency problem also makes the company engaged in a more positive tax avoidance behavior. At the same time, this study also compared the using of instrumental variables. We found there is an indeed and endogenous relationship between the directors and supervisors pledge and corporate tax avoidance.