The invention discloses a rectifying circuit for a ship shore power system. The circuit comprises a first bridge arm, a second bridge arm and a third bridge arm, wherein the first bridge arm and the second bridge arm are connected in parallel; the second bridge arm and the third bridge arm are connected in parallel; the first bridge arm and the third bridge arm are connected in parallel; the first bridge arm comprises multiple rectifying modules; two smoothing reactors are connected in series at the middle of the first bridge arm; the rectifying module comprises a rectifying unit and a capacitor; the rectifying unit and the capacitor are of a parallel structure; the first bridge arm, the second bridge arm and the third bridge arm are internally provided with the same number of rectifying modules; and the rectifying unit comprises a first triode, a second triode, a first diode, a second diode, a first capacitor, a second capacitor and a full-bridge rectifying sub-unit. By adopting the rectifying circuit disclosed by the invention, alternating current in a power grid can be converted into medium-voltage direct current required in the shore power system, and the direct current can be stably output.