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 references for the surgical treatment and rehabilitation of patients. Methods A total of 31 patients with medial single compartmental KOA after unilateral MOWHTO treatment were selected as the experimental group, and 35 healthy subjects at same age were selected as the control group. The Pedomedic 40 ?? pressure measuring system was used to test dynamic plantar pressure. By comparing the maximum pressure ( pmax ), 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 during 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 1st metatarsal head (MH1) were higher (P<0. 05), the CA of the 4th metatarsal head (MH4)was smaller (P<0. 001), the pmax and FTI of the 5th 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 pmax of MH1 and MH2 was smaller (P<0. 05), the CA and FTI of MH5 were larger (P<0. 05), the pmax of MF-L was larger (P<0. 001), and the FTI of lateral rear foot (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 necessary to restore the normal plantar distributions of patients.