In this study, we present the development of a smart, dual-axis continuous passive motion (CPM) rehabilitation device for patients undergoing total hip arthroplasty. Most commercial CPM systems provide only uniaxial flexion–extension motion, limiting their application in comprehensive hip rehabilitation. The proposed system introduces an additional abduction mechanism to enable multidirectional movement during postoperative recovery. The mechanical structure adopts a modular design that allows an independent assembly of the flexion and abduction modules. A programmable logic controller (PLC)-based electrical control unit integrated with a human–machine interface (HMI) was developed for coordinated dual-axis operation. Four endpoint position sensors were installed at the 0 and 90° limits of the flexion module and the 0 and 30° limits of the abduction module. Intermediate positions are controlled by the PLC according to the stepper-motor pulse count and linear-actuator stroke, while the endpoint position sensors provide origin confirmation, travel-limit detection, and overtravel protection. Under abnormal overtravel conditions, the PLC stops the corresponding motion and displays a warning on the HMI. Functional testing confirmed smooth and stable dual-axis operation. These results demonstrate the feasibility of the proposed system and indicate greater motion versatility and integrated control functionality than conventional single-axis CPM configurations, supporting its potential for future clinical application.