Abstract: In order to explore the influence of environmental humidity on the measurement accuracy of coal dust concentration, on the basis of analyzing the principle of the three main methods of dust measurement: laser scattering method, β-ray method and charge sensing method, the measurement of coal dust concentration and its error were carried out under different humidity conditions, and their respective compensation methods were put forward. The experimental results of coal dust concentration measurement show that when the relative humidity is 50%, the error of this three methods is less than 7%; when relative humidity is from 60% to 70%, the error of laser scattering method is more than 20%, the maximum error of β-ray method and charge sensing method is about 15%; when the relative humidity is greater than 70%, the error of the three methods is large. To eliminate the influence of humidity, the laser scattering method and the charge sensing method are added the humidity detection system, the laser scattering method adjusts the mass concentration conversion coefficient according to the humidity, the charge sensing method adjusts the coefficients of the algorithm according to the humidity, and the β-ray method uses the dynamic heating compensation method.