The invention discloses a robot accuracy compensation method synthesizing a pose error model and rigidity compensation. The method comprises the following steps: step 1, establishing a robot motion model according to structural parameter of a robot; step 2, establishing a robot error model; step 3, in a robot working space, randomly giving a target pose point, and when a tail end of the robot moves a designated point, recording a joint angle at the moment; step 4, using a position measuring instrument to measure actual coordinates Pa of the given target pose point; step 5, using a least square method to recognize an error parameter; step 6, applying a load at the tail end of the robot, measuring the deformation amount of the robot, then returning to step 3, compensating a re-recognized structural error for the motion model again, thereby eliminating the pose error of the tail end due to the deformation caused by the load, and meanwhile, data of the deformation amount caused by the load is stored in a database for later accuracy compensation. According to the invention, the absolute positioning accuracy of the robot can be improved remarkably, and high simplicity and high efficiency are realized.