This paper analyses the status and advantages of automatic test for relay protection device, and describes a set of automatic test system for relay protection device according to the characteristics and requirements of test performance in product development. The distribution architecture and module design concept are adopted by the test system, and a real-time test script is designed based on Python. The test system can realize close loop automatic test and regression test for relays protection device. The system can provide automatic test of relay protection device for conventional substaion or digital substation by modifying its configuration. Each module is described from the aspects of the design explicitly and implementation of test case is emphasized. The proposed system can improve the efficiency and guarantee the quality in practical application of testing process for products development.