[Objective] Canned permanent magnet synchronous motor(CPMSM) is widely used in high-demand industrial fields due to its excellent safety and tightness, and is mostly powered by frequency converter. However, the time harmonic current generated by the frequency converter will lead to electromagnetic disturbance inside the generator, change the coupling characteristics of multi-physical fields, and cause forced deformation of the shielding can. Long-term operation may lead to structural fatigue and even motor damage. Therefore, in-depth study of the influence of harmonic current on the electromagnetic force per unit length distribution and structural response of the can is of great significance for revealing the deformation mechanism, optimizing the motor design and improving the operational reliability. [Methods] In this paper, a 1.5 kW, 9 000 r/min CPMSM was taken as the object to carry out the joint simulation of electromagnetic field and structural field. Firstly, based on the electromagnetic field theory, the analytical formula of radial electromagnetic force considering time harmonic current was derived. Then, the simulation model of CPMSM was constructed. By applying harmonic currents with different parameters, the electromagnetic force per unit length on the inner side of the can was calculated, and the forced deformation response of the can of three stainless steel materials of SUS304, SUS316, SUS430 was analyzed. [Results] The simulation results showed that the electromagnetic force per unit length increases with the increase of the amplitude of the time harmonic current, and the frequency of the electromagnetic force increases with the increase of the number of time harmonic current, but the amplitude was basically unchanged. There was a cosine relationship between the electromagnetic force per unit length and the phase angle, which has obvious modulation characteristics. Among them, SUS430 material had the largest electromagnetic force per unit length and deformation under the same excitation due to its high permeability. [Conclusion] This study reveals the influence of time harmonic current on the electromagnetic force per unit length distribution of the motor and the forced deformation of the can. It provides a theoretical basis for motor structure optimization and harmonic suppression. It is of engineering significance to improve the operation stability, and also provides a reference for the design and material selection of the can.