Aiming at the problems of low power factor and harmonic current in mine low-voltage grid, a PWM waveform modulation method was proposed, which was applied to mine low-voltage static var generators (SVG, Static Var Generators). The current harmonic generated by this method was small, the power factor can be adjusted to the required power factor, and the algorithm was simple and easy to implement. The algorithm in this paper calculated the turn-on and turn-off time of the controllable device according to the required power factor and current, and then controlled the current required by the controllable device. In order to detect the harmonic components of the generated current, the p-q method was added to detect the current harmonics. The three-phase circuit was simulated by Matlab to verify the effectiveness of the algorithm. The simulation results showed that the current harmonic component generated by this method was small and the power factor could be adjusted. The article had certain guiding significance for the realization of PWM control strategy.