Abstract: In view of the problem that pure water injection was inefficient in dust reduction and the compound surfactant was complex in coal seam,the surfactant OP-10 was selected as the additive for the study of water injection and dust reduction in coal seam.By means of contact angle,surface tension measurement and Fourier transform infrared spectrum,the influence of different concentration of OP-10 on wettability of lean coal,coking coal and long-flame coal with different metamorphism was studied.The results show that under the same concentration of OP-10,the contact angle of coal sample first increases and then decreases with the increase of metamorphism;when the coal quality is the same,the concentration of OP-10 solution has a negative correlation with contact angle and surface tension in a certain range.In the application of water injection in coal seam,after the OP-10 with the volume fraction of 0.2% is added,the total dust concentration of dust reduction rate is from 34.4% to 60.8%,average dust reduction rate is 47.6%,and the dust reduction efficiency is significantly improved.