Objective To analyze the plantar pressure distribution of knee osteoarthritis (KOA) patients after medial opening wedge high tibial osteotomy (MOWHTO), so as to provide biomechanical reference for the surgical treatment and rehabilitation of patients. Methods 31 patients with medial single compartmental koa after unilateral MOWHTO treatment were selected as the experimental group, and 35 healthy people of the same age were selected as the control group. The Pedomedic 40? pressure measuring system tests the dynamic plantar ressure. By comparing the max pressure (max-p), force-time integral (FTI) and contact area (CA) of different plantar zones between the experimental group (operative side and unoperated side) and the control group under walking, the changes of plantar pressure in patients with medial single compartmental KOA after MOWHTO were evaluated. Results Compared with the unoperated side and the control group, the CA and FTI of the first metatarsal head (MH1) were higher（P＜0.05）, the CA of the fourth metatarsal head (MH4) was smaller（P＜0.001）, the Max-P and FTI of the fifth metatarsal head (MH5) were smaller（P＜0.05）, the CA of the lateral middle foot (MF-L) was smaller（P＜0.001）, and the CA of the medial rear foot (RF-M) was larger（P＜0.05）. Compared with the control group, the Max-P of MH1 and MH2 was smaller（P＜0.05）, the CA and FTI of MH5 were larger（P＜0.05）, the Max-P of MF-L was larger（P＜0.001）, and the FTI of RF-L was larger（P＜0.05）. Conclusions Compared with healthy people, patients with medial single compartmental KOA have abnormal plantar pressure residual after MOWHTO. In clinical practice, targeted intensive rehabilitation therapy is also necessary to restore the normal plantar distribution of patients.