Abstract: According to a low electric power quality problem existed in coal mine, a three-level and four bridge-arms power filter of current harmonic compensation device was provided.Based on a conventional two-level and four bridge-arms space vector modulation algorithm, the complicated three-level space vector control was s implified to two parts of a reference level state selection and a two-level and four bridge-arms space vector control for a design method.According to the given number harmonic current compensation condition required in the coal mine grid, a control strategy of an active power filter was studied based on the divided frequency control i dea.The result was conducted with the simulation and experiment.Based on five harmonic as an example, after the compensation with the three-level and four bridge-ar ms active power filter, the five harmonic contents were reduced by about 70%.The feasibility and advantage of the three-level and four bridge-arms active power filter a pplied to the mine harmonic compensation was approved.