Shore-to-ship transformer is an important power equipment in the port shore-to-ship power supply system, compared with the influence of the traditional transformer magnetizing inrush current, the magnetizing inrush current of ship transformer will not only cause the transformer's own relay protection device to malfunction, but also cause overcurrent trip of the frequency conversion power and misoperation of shore power system's own protection. In order to study the influencing factors of inrush current and its suppression methods in shore power system, the mathematical analytical expressions of the magnetizing inrush current when the secondary side of the ship transformer is Y and △ are deduced in detail. Based on this, a ship transformer simulation platform is built in PSCAD/EMTDC，the influence of variable factors such as core remanence and resistance on the dynamic characteristics of magnetizing inrush current is deeply studied, and the corresponding suggestions are given to suppress the magnetizing inrush current. Simulation model is combined with actual parameters of ship transformer, and the correctness of the theoretical analysis is verified, which provides a theoretical basis for solving problems in practical engineering.