This study aims to analyze the effect of earnings management on firm value with the mechanism of Good Corporate Governance as a moderating variable. The sampling technique used was purposive sampling. The study was conducted on Property and Real Estate Companies listed on the Indonesia Stock Exchange in the period 2012-2017. The analytical method used is multiple regression analysis. The purpose of this study is to find out whether earnings management is able to influence the value of the company with the mechanism of Good Corporate Governance as a moderating variable. The expected results of this study are Profit Management that can influence the Corporate Value which is moderated by the Good Corporate Governance mechanism. The results of this study indicate that Profit Management has no effect on Firm Value. Simultaneously the four mechanisms of Good Corporate Governance, namely the Board of Independent Commissioners, Institutional Ownership, Managerial Ownership, and the Audit Committee have a significant positive effect on Firm Values. But partially only Audit Committees have a significant positive effect on Firm Value. While the variables of the Independent Board of Commissioners, Institutional Ownership, and Managerial Ownership do not affect the Firm Value. Of the four Good Corporate Governance mechanisms, only the Independent Board of Commissioners and Managerial Ownerships is a moderating variable that can weaken the effect of Profit Management on Firm Value.