General project management focuses on time planning and progress schedule control, earned value management approach, which not only provides a cost and time variation and performance indicators, and can also predict the cost and schedule to complete the project. This study is to investigate project management with defects for the develop-ment of earned value model to obtain the impact of the investment on the quality. Basic indicators related to the use of earned value management can be with respect to cost and schedule. According to the reference data from Anbari (2003), the first stage and the second stage of the project are corresponding to the defective rate q1 and q2, for the development of the earned value of poor quality in the model and their effects. The optimal quality level of each stage can be obtained to minimize the total actual cost and attain the cost/benefit of the project.