Abstract: The coal seam in No. 11071 working face of Zhenxing No.2 Mine had complicated conditions of softness, poor-permeability and floor undulation.Accordin g to the poor dust control effect with usual water injection technology, the borehole layout mode and the effect of water injection were studied for coal seam under comp licated condition.The boreholes drilling along seam were arranged along the tailgate and the high level borehole was arranged in the coal seam with floor undulation for water injection.The short boreholes were arranged along the working face for water injection.Combined with practical experience, the major technical parameters of bor ehole were determined.After the improvement of borehole layout mode and its technical parameters, the average of dustproof ratio of working face was raised from 40% to 63.44%.