Abstract: Aiming at the nonlinearity and nonstationarity of analog circuit fault signals, a fault diagnosis method based on ensemble empirical mode decomposition (EEMD) combined with multi-scale entropy and least square support vector machine (LSSVM) is proposed. In this method, the set empirical mode decomposition algorithm is used to decompose the output response signal to get the intrinsic mode components, then the multi-scale entropy of each component is obtained and the fault eigenvectors are constructed. Finally, the fault eigenvectors are input into LSSVM classifier for detection.The experimental results show that this method can effectively extract fault feature information of analog circuits, and achieve accurate fault diagnosis of analog circuits.