In China's capital market, there are controlling shareholders in most listed companies. Controllingshareholders are inclined to use their over-controlling rights to occupy resources, and therefore leading toinefficient investment. Simultaneously, the corporate governance mechanism could also perform oversightfunctions, coordinate the interests of all parties and restrict inefficient investment behavior. Combininganalytical with empirical research, we are tend to explore the investment behaviors under principal-principalconflicts and corporate governance. We used a mathematical model and then empirical model to explore theunidirectional influences which principal-principal conflicts imposed on inefficient investments and corporategovernance imposed on governance. And the results of analysis showed that corporate governance will weakenthe impact of the conflict of interest on inefficient investments, and conflicts of interest suppress the role ofcorporate governance on inefficient investments.