A visible calculation and management system for generator’s internal faults and main protective relaying setting is developed. With the advanced visible programming technology, the system can integrate the protection information on the graphic interface. The system is based on VC++. In order to enhance its universality, the system uses graphic interface as its foreground application, and uses interface program to visit background database. The function and feature of each module of the system are introduced. Based on the transient-state analysis of generator’s internal faults, the protection setting is easy to be completed, which also enhances the reliability of the relay protection. Field tests show it can improve the accuracy of the setting of relay protection.