Considering the characteristics of smart substation, such as complex functions, various products and high real time requirement, this paper designs an integrated tester with full functionality and reliable testing. The tester supports performance testing of the station control layer monitoring system, bay layer IED, the process layer device, switches, timing device, etc. On the basis of predefined test cases and process, it can automatically carry out the positive and negative test, and generate the test report which is convenient for searching and correcting the test defects. This tester significantly improves the efficiency and quality of test with solving the limitation and deficiency of test function. According to typical verification by testing in related equipment, the integrated tester shows good performance which meets the expected goal. This work is supported by Shandong Technical Innovation Project (No. 201711901062).