Abstract: Based on the analysis on the topological structure of the mechanical structure of cantilever roadheader,the compensable elevation angle,roof pitch and roll angle deviation of parallel walking/supporting mechanism in the working/rolling plane,the compensable horizontal angle,horizontal deviation and forehead deviation in rotating/lifting mechanism in horizontal plane are respectively analyzed,the mathematical model of spatial position and posture deviation of roadheader is established for the first time.Applying the forward/inverse solution of spatial mechanism structure and solution of MATLAB,the instantaneous position and attitude deviation information of the fuselage movingplatform is obtained when the geometric parameters of each structural loop are known.When the fuselage is in the limit state of compostable space position and attitude deviation,the adjustable geometric structure parameters of corresponding cantilever roadheader are obtained by the inverse solution.The results meet the requirements of engineering design.The simulation results show that the maximum compensated elevation deviation is 26.731°,the maximum pitch deviation is 27.468° and the maximum top distance deviation is 20.253 7 mm by adjusting front-shovel/plateback hydraulic cylinder,and the maximum compensated horizontal deviation is 36.067 degree by adjusting the cutting arm’s cutting attitude dynamically.The experimental results also prove the validity and efficiency of the proposed model.The mathematical model of spatial position and attitude deviation proposed in this paper can provide an effective basis for the implementation of intelligent and precise deviation rectification for cantilever roadheader dynamic in realtime.