Abstract: Dynamic supply current test is very useful for fault diagnosis in analog circuits.In order to improve the defect of wavelet neural network in fault diagnosis in analog circuits I_DDT ，a method of fault diagnosis in analog circuits I_DDT based on multiwavelet neural network is proposed.Multiwavelet transform is used to extract each frequency’s energy of current of power supply.Then the energy is used as input vector of neural network for fault diagnosis.Simulation results indicate that this method is effective，multiwavelet neural network converges more rapidly than wavelet neural network.