This paper proposes a multi-objective optimization design method for brushless DC motors by combining the scanning method with genetic algorithm. This method can achieve rapid motor optimization design while ensuring computational accuracy. The stator tooth width, stator yoke thickness, permanent magnet thickness, and permanent magnet thickening thickness of the brushless DC motor are taken as optimization variables, and the average electromagnetic torque and torque ripple are set as the optimization targets. The scanning method and genetic algorithm are combined for global optimization to obtain a better motor design scheme. The optimization analysis demonstrates a 5.07% enhancement in the electromagnetic torque of the optimized motor, accompanied by a notable 15.8% reduction in torque ripple, validating the effectiveness and practicality of the combined scanning method and genetic algorithm optimization approach.