With the development of manufacturing automation, the requirements of market for fluid power products are higher and higher. But the existing hydraulic cylinder products with single property and less motion patterns can not meet the requirements of market day by day. In view of this question, a new rotary motion and linear motion combined hydraulic cylinder was designed. Using the features that ball spline pair could transfer torque and realize linear motion, double screw swing hydraulic cylinder and traditional reciprocating linear motion hydraulic cylinder were integrated, not only single reciprocating linear motion and rotary motion could be realized, but also complicated rotary motion and linear motion combined movement could be realized. It is of good technical performance, compactsized, large output load, high transmission efficiency, steady transmission, easy installation, and can satisfy the market’〖KG-*2〗s demands for hydraulic transmission products with various properties.