Abstract: Objective To explore the biomechanical changes of gait after total knee arthroplasty (TKA). Methods The gait data were collected from 18 unilateral TKA patients and 18 healthy subjects. The changes of gait parameters were compared between the surgical and health sides in the TKA group and also between the TKA and control groups. Results Compared with the control group, the TKA group presented remarkable decreases in step length, step frequency, walking speed, swing phase, the maximum flexion and the sagittal range of motion for the knee joint. Moreover, the TKA group showed decreases in the peak flexion torques of the lower limb joint, the peak ground reaction force in vertical and anteroposterior directions, compared with the control group. For the TKA group, the surgical side presented significant decreases in the maximum flexion and flexion-extension range within the knee joint, the ankle sagittal range of motion, and the medial peak of ground reaction force compared with the health side. Conclusions TKA patients show good gait symmetry after surgery, which however does not get back to normal; and post-operative rehabilitation training is still needed.