Abstract: Aiming at poor efficiency, inapplicable for wide input voltage occasion and direct conduction under traditional synchronous rectification forward converter, an improved synchronous rectification forward converter is proposed. The MOSFET of the improved converter is driven by both ends voltage of auxiliary winding. This converter has high efficiency, applicable for wide input voltage occasion and can solve the problem of direct conduction. The operating principle and the operating mode of the improved synchronous rectification forward converter are analyzed. The Euler-lagrange(EL) model of the synchronous rectification forward converter is established. Based on passivity based control theory, a passivity based controller of the improved synchronous rectification forward converter is designed by damping injection method. Good dynamic and static performance and robustness to load change of the improved synchronous rectification forward converter is achieved through the passivity-based controller. The simulation and experimental results show that the converter and its passivity based controller are feasible.