The characteristics of share structure of listed company subject to be tunneled were studied. The market response of related party transactions was examined by event study method. It is confirmed that the largest shareholder tunnels listed company in this way. It is seen through regression analysis that when the largest shareholder controls listed company in a complicated way, the control rights and cash flow rights separate deeper, which inspire the largest shareholder tunnel. Moreover, the ultimate controller of listed company was divided into four groups to study. Some suggestions are also given.