[Objective] This paper proposes a harmonic elimination slot structure for the rotor bars of a 5.5 kW inverter-fed squirrel-cage induction motor, aiming to improve the current density distribution in the rotor bars and minimize local hot spots near the slot openings. [Methods] The analysis was initially conducted based on magnetomotive force and magnetic permeability to examine the air-gap magnetic field components and induced harmonics current in the rotor bars of the induction motor. The penetration depths of different harmonics current were calculated according to the skin effect. Subsequently, a mathematical model was established for the current-carrying area of individual bars as a function of harmonic elimination slot geometry and parameters, derived from the rotor slot opening geometric model. An optimization design process for the harmonic elimination slots was proposed by combining this mathematical model with limited simulation data. Finally, the optimal parameters for the rotor harmonic elimination slots of the specified induction motor were determined through simulation verification. [Results] Through simulation analysis, it was found that under no-load conditions, the rotor harmonic elimination slots reduced harmonic copper losses by 40.9%; under full-load conditions, a reduction of 5.5% was achieved. Additionally, the current-carrying area of the bars decreased by only 0.94%, indicating that the harmonic elimination slots did not significantly affect other electromagnetic performance in both operating conditions. [Conclusion] The proposed rotor harmonic elimination slots in this paper can significantly reduce rotor harmonic copper losses, leading to a more uniform current distribution in the bars. This effectively mitigates local thermal stress and temperature rise in high-load motors, making it suitable for motor operating conditions with frequent start-stop cycles or power supply containing harmonics.