Hydraulic cylinders with built-in piston-rods have many distinct advantages, such as good structural compactness and high rigidity. However, other mechanisms need to be series connected with it in order to output the expected force and motion. An innovative design of changing the structure of the piston-rod built-in cylinder and many reconfigurable hydraulic-mechanical combined drive devices is introduced in this paper. Several kinds of detailed devices and corresponding mechanical calculating formulas are given, characteristic features of these devices are analyzed too. The results clearly show that quick reconfigurable hydraulic-mechanical combined drive devices with multi-functions can be innovatively designed solely by changing the geometric figure of the piston-rod built-in cylinder, while the basic structure of the cylinder block assembly and piston assembly is unnecessary to be changed. By this means relevant products with advantages of low cost, high capability and flexibility, short empolder period and man-hour will be obtained in practice.