The invention relates to a biology fusion foot joint return robot, which is characterized in that: the upper ends of four straight drivers are connected to the mounting support (5) of upper platform (16) via universal hinge (4), while the lower ends via ball couples (9) are connected to the lower platform (12); feet (11) via clamper are connected to the lower platform (12); the leg (2) via fixer is connected to the upper platform (16); the straight driver (6) can be lead screw nut device, bidirectional movable cylinder (22) or electric cylinder (33). The invention is based on bionic technique,to fuse the under-knee part of human as branch into system. The invention has several freedoms, to realize complex return movements, while the rotation hinge point is layered with feet joint rotationhinge point. And the data can be used in diagnosis.