Evaluating software quality is a significant step in the process of developing software. Object-oriented metrics is an important way for software quality assessment and defect prediction. However, the existing object-oriented metric methods are difficult to reflect the complexity of software and vulnerabilities from the level of classes' method call relationship. A method is proposed in this paper, firstly we construct a call graph according to different classes methods call relationship in the system, and then three new software metrics are defined and analyzed by the call graph. The results of experiment indict that the metrics can reflect the complexity of software systems. These metrics can provide recommendations for evaluating software quality from the call graph.