The invention discloses a micro precision machine tool capable of finishing machining a free curved surface at a time. The micro precision machine tool capable of finishing machining the free curved surface at a time is characterized by comprising a rack, a shock absorbing base, a driving assembly, a tool bit assembly, a workbench and a clamp. The rack is placed on the shock absorbing base; a machining head assembly is installed in a normal-triple-prism inner cavity defined by the rack; an X direction linear motor, a Y direction linear motor, a hydraulic cylinder piston rod, a gear pair and the like of the driving assembly coordinate and cooperate with each other, and a to-be-machined piece can be driven to move in the front, back, left and right directions, to overturn in the vertical direction, and to rotate along the horizontal plane; the tool bit assembly is driven by a Z direction linear motor to move up and down; and after the to-be-machined piece is clamped and fixed one time, machining of a plane or the free curved face can be completed. The body portion of the micro precision machine tool capable of finishing machining the free curved surface at a time is all installed in a tetrahedron structure space which is quite stable, and the micro precision machine tool capable of finishing machining the free curved surface at a time is compact in structure, reasonable in arrangement, high in machining precision, good in reliability and stability, capable of finishing machining and forming the free curved surface at a time, and the like.