The invention relates to the technical field of power equipment detection, and especially relates to an analog-digital mixed circuit fault diagnosis test method based on an expert system. The test method is implemented through a traditional expert system by applying transient response test to analog-digital mixed circuit fault diagnosis. The system comprises a knowledge base and a reasoning machine. The establishment of the knowledge base includes knowledge acquisition, fact signs of a measured object, a rule base, and a database. The reasoning machine includes an explanation mechanism and a man-machine interface. The test method has high fault coverage rate. Only an input node and an output node need monitoring. Test point selection is avoided. The operation is convenient. Another advantage of transient response test is that the speed is usually higher than that of traditional small signal test or static test. By using the test method, the test process is simplified greatly, the test time and cost are reduced, and the working effect is improved greatly. The test method is more suitable for practical engineering application.