Abstract: Objective To study the effect of different posterior slope installations of unicompartmental knee arthroplasty (UKA) prosthesis on the knee joint loading, motion and tibial insert wear. Methods This study utilized a combined approach involving UKA musculoskeletal multibody dynamic model, finite element model, and wear prediction model to investigate the effects of five different posterior slope installation position of UKA prosthesis on postoperative knee joint force and motion, insert contact stress, linear wear depth, and wear volume. Results As the posterior slope angle of the UKA prosthesis increased, the internal rotation and posterior translation during the gait cycle increased, the medial joint force during the swing phase increased, the Von Mises stress and contact stress of the insert after 5 million wear cycles decreased significantly, and the wear area, the maximum linear wear depth and the volumetric wear volume of the insert were reduced consequently. Compared with the posterior slope of 0°, the linear wear depths of the insert for the posterior slopes of 3°, 5°, and 7° decreased by 17.8%, 19.2% and 20.6%, respectively; and the volumetric wear volumes of the insert decreased by 24.5%, 30.9%, and 34.3%, respectively. Conclusion Installing UKA prosthesis with a posterior slope exceeding 3° significantly would increase the internal rotation and posterior translation during the gait cycle, further reduce articular volumetric wear of the polyethylene insert .