The relative position and orientation deviation is unavoidable when industrial robots use the end actuator to clamp loads. The deviation have a certain influence on the data of six-dimensional force/torque sensor fixed on the end of manipulator. In this paper, we propose an algorithm, in which the gravity, inertia force, Coriolis force and the centripetal force of the load are analyzed when the mass and shape of the load are known and the trajectory of manipulator is fixed, then the relative position and orientation deviation between actuator and the load can be determined by linear equation and particle swarm optimization, respectively. Finally, the feasibility of the algorithm is verified by MATLAB and Adams simulation.