According to the failure problem which might be occurred in the application of a sapceborne bus system, a test method for the physical layer and protocol layer of a 1553B bus is proposed. In the method, the test of the electric characteristics of the physical layer includes the analysis of voltage, waveform, code, etc. The test of the complex protocol layer includes the analysis of instruction transmission, address recognition, effective data, check bit and message interval, etc. Finally, the validity and practical applicability of this test method are verified experimentally.