For large ring laser gyroscope (RLG),lasers require more accurate and more stable excitation power supplies.Aiming at the poor output performance of single-ended flyback converter,a single-ended flyback converter with capacitor-inductor-capacitor (CLC) filter is designed by adding capacitors and inductor to the output end of the traditional flyback converter.On this basis,the static working point of the converter is determined by using the switch elements average model method,and the fourth-order small signal model operating in continuous conduction mode (CCM) is established.The correlation transfer function is derived and the phase leading correction is introduced into the system to improve its stability.The system model of proportion-integral-differential (PID) control is established via MATLAB,and the analysis and verification of flyback converter with CLC filter is completed.The results show that the model established by small signal modeling theory is reasonable and available,which is helpful for the design and optimization of laser excitation power supply.