Abstract: In order to realize the TC21 complex rotary component turning and milling composite flexible fast and stable clamping, this paper designs a set of turning and milling composite flexible quick-change clamping system from the aspects of process boss, fixture structure, hydraulic system, positioning accuracy calculation and clamping strength calculation, based on the zero point positioning system. Practice has proved that the system can achieve accurate positioning, fast and stable clamping, and solve the problem that the workpiece clamping time is long and the deflection occurs during processing, and can meet the flexible and quick change of different workpieces of turning and milling, and has good versatility.