By analyzing overvoltage at food motor end, it is determined that the inverter output (rise/fall time of voltage pulse), the nondestructive cable parameters (inductance, capacitance and length) and the characteristic impedance of food motor are the main influence factors affecting overvoltage at food motor end in PWM inverter fed induction food motor system. Mathematic formulas and simulations for factors are carried out firstly and then the weight of every factor is determined based on the BP neural network. All the study in this study has certain guiding significance for the analysis and design of PWM inverter fed induction food motor system.