Taking certain types CNC camshaft grinder as the research object, through the analysis of the structure and movement of it to determine the total of 21 error parameters. By establishing the motion relation model of the adjacent body coordinate system contains the error parameters. The machine movement is divided into "bed - workpieces " and "bed - tool " two kinematic chain. It established the topology structure of the machine tool, and then using the multi-body system theory to the modeling error of the machine tool. Each moving bodies were set up body coordinate system and motion reference coordinate system. It solved corresponding transformation matrix by combining with the motion relation model of the adjacent body coordinate system. It put forward in case of using errors affect achieve precision machining constraints equation is Pw=Pt, and solved the equation. It established mathematical model of X-C axis linkage at the time of the camshaft grinding, and worked out the grinding point coordinates in workpiece coordinate system and tool coordinate system. It adopted the three kinds of measurement methods for 15 error parameters identification of affecting the camshaft machining by using cue instrument. It provides necessary conditions to research on machine tool error compensation.