<p>Prosthetic knee joints play a critical role in restoring gait function in individuals with lower-limb amputation; however, conventional evaluation methods involving human participants are constrained by limitations related to safety, ethics, cost, and experimental repeatability. To address these challenges, this study proposes a robotic gait simulation platform for systematic evaluation of prosthetic knee kinematics and control performance. The proposed 3-DOF gait simulator generates hip trajectory-driven motion through synchronized horizontal translation, vertical displacement, and hip flexion–extension rotation. Validation experiments demonstrated that the simulator reproduced reference hip joint trajectories with high accuracy. Using the proposed platform, both a passive prosthetic knee (Ottobock 3R60) and a microprocessor-controlled prosthetic knee (MPK) were experimentally evaluated. The passive prosthetic knee exhibited simulated knee joint trajectories showing high agreement with experimentally measured transfemoral amputee knee kinematics, and the MPK demonstrated highly repeatable and stable performance under repeated operating conditions. Threshold-based control verification confirmed reliable operation of the control logic under various input conditions, and cyclic loading tests verified structural reliability under repetitive operating conditions. Furthermore, knee joint torque analysis revealed consistent cyclic torque generation patterns during simulated gait. These results demonstrate that the proposed simulator can reliably generate hip trajectory-driven motion based on predefined reference trajectories and serve as a repeatable platform for quantitative preclinical assessment of prosthetic knee kinematics, control performance, and mechanical reliability without requiring human participants.</p>