The high-speed maglev system based on linear doubly-fed motor (LDFM) can use the bidirectional power transmission capacity to realize contactless power supply at low speed, which will greatly improve the reliability and operation cost of maglev train. The performance of LDFM is analyzed in detail by using the finite element analysis method. Taking low electromagnetic force fluctuation as optimization objective, the sensitivity of key dimension parameters is stratified based on sensitivity analysis. According to the parameter sensitivity level, the multi-objective optimization analysis based on genetic algorithm and single parameter scanning method are combined to determine the optimal parameters of the motor. The thrust force and suspension force of the motor are analyzed and calculated by 2D finite element method, which verifies the effectiveness of the proposed system and motor design method.