In order to improve the power factor, mining enterprises used a large number of parallel capacitor, but its harmonic current is larger, aiming at this phenomenon, the paper used the method of parallel capacitor concatenated a certain size reactor, to improve the resonance point of parallel capacitor and system impedance, eliminated the system harmonic. There designed the simulation model of ball mill asynchronous motor reactive power compensation device, from the results, the reactive power compensation and harmonic governance had better results for the device