Abstract: In view of problem that existing mechanical compensation methods of lever arm effect ca't get angular acceleration information in real time, an improved method of lever arm effect error compensation was proposed on the basis of analyzing cause of lever arm effect on strap-down inertial navigation positioning system of shearer.The method uses same component of the gravity acceleration information at different moments of navigation coordinate system to obtain length of lever arm.Then, it adopts the angular velocity to determine the angular acceleration of the carrier coordinate system with respect to the navigation coordinate system. Finally, it uses lever effect error equation to calculate the error of measured acceleration to compensate the output acceleration. The simulation results show that the error compensation method can improve precision of the strap-down inertial navigation positioning system of shearer, and compensate position error of shearer effectively to remove cumulative error. Compared with the uncompensated methods, the positioning accuracy of the shearer in x direction and y direction improves 5.1% and 23.6% respectively.