Abstract: From the viewpoint of system engineering, a useful framework was explored for software reliability comprehensive evaluation based on grey system theory which has been acknowledged as a powerful technique for system comprehensive evaluation. According to the software quality model in ISO/IEC 9126, software reliability metrics were regarded as the evaluation index, and the grey relational degree between each metric and reliability was analyzed which can be used to identify the weights of metrics. Consequently the software reliability comprehensive evaluation method based on grey cluster theory was proposed. Finally, a primary experiment research was conducted to show that the framework for software reliability comprehensive evaluation based on grey system theory can reflect the level of reliability accurately with the values of these reliability metrics which can be collected easily in each development phase. Therefore the proposed framework is suitable for reliability engineering practice.