Software testing plays a vital role in producing reliable software. The debugging of software is divided into two steps:fault localization and fault modification, where the fault localization is the most time-consuming and tedious work. Generally, most of test cases in a test suite performed successfully. In order to improve the availability of the defect location method based on the program spectrum, the method should have the ability to adjust the weight of successful coverage automatically. That is, if the contribution of the number of statements to the suspiciousness is reduced gradually with the increase of the number of successful test cases, the effectiveness of fault localization method can be improved greatly. Based on this idea, this study proposes an EPStar (EP*) defect location method, which can effectively adjust the effect of successful use cases, so as to avoid the excessive influence of the number of successful use cases to the defect location effect. To improve the accuracy of error location, the experimental comparison shows that EP* method has higher defect location accuracy than several existing defect location methods.