Obiective To build a personalized musculoskeletal multi-body dynamics model of total knee replacement by two free software nmsbuilder and opensim， and verify the model use bouncy and medthrust two gait pattners by comparing results of experiment and model. Methods Based on MRI and STL skeletal data from patient, bodys, skeletal landmark clouds and muscular landmark clouds were established for reference systems and muscles automatically. Results In addition to the lateral joint contact forces, the magnitude and trend of the knee joint contact forces which the model predicted have a good agreement with the experimental data，the constructed skeletal muscle multi-body dynamics model can be used for knee joint research. Conclusions The established musculoskeletal multi-body dynamics model predicts the medial, lateral, and total tibiofemoral joint contact forces simultaneously by inputting the position of markers and the ground reaction forces. The ideas of this study can be used to design personalized knee prostheses. A "virtual surgery" is performed after collecting the patient's preoperative gait data and skeletal data to find the most suitable prosthesis for the patient, or further, to design a personalized prosthesis suitable for the patient.