In order to establish the equivalent model of the electro-optical servo system， it is necessary to analyze the electromagnetic interference of the system. Based on the non ideal characteristics of electronic circuit devices and the parasitic characteristics of coupling paths， the behavior level simulation model of servo drive circuit is established. Combined with ANSYS software platform， multi domain collaborative simulation is carried out to predict conducted interference emission. Through the model， the influence of high frequency drive and RC absorption circuit on interference characteristics are quantitatively demonstrated. In the test platform， it is verified that the trend of the frequency spectrum curve between 150 kHz and 10 MHz is basically consistent with the measured spectrum curve， which indicates that the model can be used as a feasible scheme to predict and evaluate the electromagnetic compatibility of servo drivers.