The invention relates to an electromagnetic compatibility test method and device for electric power online monitoring equipment. The method comprises the following steps of: (1) performing communication connection on a tested sample and an electromagnetic compatibility tester, and judging whether the connection is successful, if the connection is successful, executing the step (2), or otherwise, continuing executing the step (1); (2) testing the electromagnetic compatibility of the tested sample through the electromagnetic compatibility tester, encrypting tested data and transmitting the tested data to an upper computer through a wireless transmission network; and (3) decrypting the tested data received by the upper computer, and matching and comparing the test data with the data in a database to obtain a rest result of the tested sample, wherein the device comprises the electromagnetic compatibility tester, the upper computer, an insulation support, a grounding reference plane and a non-metal pedestal. Compared with the prior art, the electromagnetic compatibility test method and device have the advantages of wide test range, capability of remote monitoring, high test precision and the like.