Abstract: Study on the repeatability of kinematically redundant manipulators under pseudoinverse control is reviewed in this paper. This work discusses whether the existence of LBC's stable surface and zero torsion of self-motion manifold as judge of the repeatability are available, clarifies the misconception with which stable surfaces are introduced to judge the repeatability, analyzes the contradiction between pseudoinverse control repeatability and redudancy, and suggests that in order to obtain free-trajectories for redundant manipulators performinging tasks with periodically closed paths, no pseudoinverse control methods but relevate control methods which decrease redundant systems to non-redundant systems be chosen.