Abstract: Objective To analysis the plantar pressure features of the injured and healthy sides at different stress positions after the Trimalleolar fracture surgery, and compare these characteristics with healthy subjects. Methods Twelve Trimalleolar fracture patients and twenty-three healthy subjects were recruited. Each subject was tested for plantar pressure at different stress positions. The evaluation indices were peak pressure, contact area and contact time percentage. Results (1) In neutral position, the peak pressure of the 3-5th toe in the affected foot was smaller than that in the healthy side; in the inversion position, the peak pressure and contact area of the 3-5th toe area were smaller than those in the healthy side; in the eversion position, the peak pressure, contact area and contact time of the 3-5th toe were smaller than those in the healthy side, and the peak pressure of the hindfoot area was larger than that in the healthy side. (2) In the three position, the peak pressures of the second and third metatarsus bones , the second toe, the 3-5th toe, the contact area of the 1-5th toe and the contact time percent of the second toe, the 3-5th toe area were all smaller than those of healthy subjects, the contact time of the hindfoot and mid-foot area were all smaller than those of healthy subjects. Conclusions The plantar pressure characteristics of Trimalleolar fracture patients are asymmetrical. Compared with healthy subjects, the plantar pressure features of patients are abnormal. Compared with healthy subjects, the motor control ability and stability of patients at eversion stress positions are decreased. The plantar pressure characteristics at ankle eversion could be used to evaluate ankle joint function.