The segmented stator structure is applied to the canned permanent magnet synchronous motor (CPMSM) can improve the performance of the motor. However, the influence of the stator module gap on the CPMSM performance is not clear. In this paper, an iterative calculation method for the electromagnetic performance of the motor is proposed. Using this method, the influence of stator module gap on the electromagnetic performance of the CPMSM with segmented stators is analyzed under the conditions of constant current and constant torque. The calculation results are compared with the finite element calculation results. The results show that under constant current, the increase of the stator module gap leads to the decrease of the loss, torque, efficiency and power factor. Under the condition of constant torque, with the increase of the stator module gap, the loss and power factor of the CPMSM are reduced, but the efficiency of the CPMSM is gradually improving. Finally, a prototype is made and a test platform is built. The test results verify the correctness and effectiveness of the proposed method and results. This study not only enriches the theoretical knowledge of the CPMSM with segmented stators, but also has practical significance for helping and guiding the design of the CPMSM.