Abstract: In order to reduce the error of measuring the drilling attitude angle parameter of MWD inclinometer in coal mine, a mathematical model of error compensation based on recursive least squares was established, the joint correction method of ellipsoid fitting method, dot product invariance method and rotation plane fitting method were used in the error compensation correction for MWD inclinometer. Numerical simulation experiment and double-axis turntable experiment were carried out on the developed MWD inclinometer, error compensation correction of experimental data was conducted with joint correction method, the maximum absolute errors of pitch angle and azimuth angle before correction are 4.7° and 5.1°, after correction are 0.8° and 0.9°, the corrected measurement accuracy meets the requirements of MWD inclinometer. Experimental results show that this method can be used to effectively compensate the error correction of MWD inclinometer in underground coal mine.