Against the structure of the phase-shifted full-bridge switching power supply system and the complexity of traditional PID controller parameter adjustment,the full-bridge switching power dynamic small-signal mathematical model was established by using the state-space averaging method firstly,and the accuracy of which was verified by simulation；then an Internal Model PID Controller was designed based on the Internal Model design principle to reduce the number of adjustable parameters and the complexity of parameters adjustment；By introducing the Fuzzy algorithms,a fuzzy internal model-PID controller was designed to take into account the dynamic performance and robust performance,Finally simulation proves the effectiveness of the designed controller．