Objective To investigate the biomechanical characteristics of Salto Talaris tibial components with different heights at the bone-prosthesis interface during different gait support phases after total ankle replacement. Methods An ankle joint model was reconstructed using a weight-bearing CT from a 61-year-old female patient with ankle arthritis, and Salto Talaris tibial components with different heights (5, 7, 9, 11 mm) were modelled to simulate the loading of the tibial-prosthesis during four gait support phases, and to analyse the micromotion and stresses at the bone-prosthesis interface. Results The 11 mm and 9 mm models had a poorer prosthesis stability, with the peak micromotion exceeding 50 μm and the peak internal tibial stresses of 30.75 MPa and 29.86 MPa, respectively, which exceeded the yield stress of the cancellous bone. The tibial stresses of the 7 mm and 5 mm models were within reasonable ranges and the average peak micromotions were only 42.66 μm and 40.32 μm. In contrast, the initial stability of the 5 mm model prosthesis was the best. Conclusions For total ankle replacement with Salto prosthesis, the height of the tibial component should be chosen appropriately, and the optimal height was about 5 mm. Excessive flexion and extension activities of the ankle joint should be avoided to maintain the stability of the prosthesis after surgery. This study provides a theoretical basis for the improvement of the structural parameters of the Salto prosthesis, which is valuable for the selection of clinical surgical prostheses and helps to improve the results of total ankle replacement.