Knee joint adhesion usually occurs after traumatic knee injuries and gout, which results in loss of functional range of motion (ROM). Various studies support static progressive stretching (SPS) for knee joints after injury to reduce risks of knee joint adhesion. Patients are required to follow a long-term rehabilitation program. Still, most patients do not adhere to their clinical therapy schedule due to rehabilitation costs, social obligations, negligence, or lack of inspiration. Moreover, the number of therapists and assessment equipment are insufficient due to the large number of patients. This study introduces a knee joint rehabilitation robot (KJRR) as a complementary tool for knee joint adhesion rehabilitation during long-term recovery that can enhance the achievement of rehabilitation goals. Our device has five degrees of freedom (5-DoF) to reach the workspace of the knee joint. Electrical and signal visualization systems are arranged to detect and display multimode signal on time. The feasibility of the proposed KJRR device is tested through forward and backward stretching with the device. The results show that the proposed KJRR fits the lower limb of subjects well and can accurately detect the required signals. KJRR device will be beneficial and used at the hospital as a complemental tool to support knee joint adhesion and better evaluate recovery.