The utility model relates to a merry go round machine quick change clamping device, including three -jaw base and circular arc annex. The three -jaw base comprises three step base, the step base has two -layer step, and the medial surface of second floor step is first locating surface, is equipped with first connecting hole on two -layer step respectively. Three circular arc annex and three step base one -to -one, the circular arc annex is for step form and has two -layer step, and the medial surface of second floor step is the circular arc pinch plane, the diameter homogeneous phase of the circular arc pinch plane of three circular arc annex etc. Be equipped with the boss in the bottom of circular arc annex, the lateral surface of boss is the second locating surface, with first locating surface cooperates into line location, be equipped with respectively on the two -layer step of circular arc annex the second connecting hole with first connecting hole is corresponding to connect the installation. Furthermore, the arc surface that first locating surface and second locating surface equal for the diameter for the orientating group will definitely be fixed a position reliably in order to strengthen.