Canned induction motor was the power source of nuclear reactor cooling circuit. It was significant to improve the efficiency and reduce the electromagnetic noise of the motor. A 20 kW nuclear canned induction motor was designed by combining the finite element method with magnetic circuit method. The main parameters that affected the motor efficiency and electromagnetic noise were determined by the simulation analysis of noise and loss under the rated operating condition with the finite element software. The main parameters that affected the efficiency and noise of the motor were selected as optimization variables, the electromagnetic noise and efficiency of the motor were the optimization objectives, and output power was the constraint condition. Sample space was obtained by the orthogonal test table, the optimization model was obtained by response surface methodology, and the particle swarm optimization was used to solve the optimization model. The finite element simulation results showed that the efficiency of the optimized motor was improved by 2.6% and the electromagnetic noise was reduced by 5.2 dB.