Objective To compare the short-term clinical effects of unicondylar knee arthroplasty (UKA) and total knee arthroplasty (TKA) in the treatment of knee osteoarthritis. Methods From January 2013 to January 2016, 61 patients with medial unicondylar knee osteoarthritis were divided into unicondylar replacement group ( n=26) and total knee arthroplasty group (n=35). The short-term clinical results of the two groups were compared. Results The difference of postoperative HSS score in both groups was not significant (P>0.05). However, the range of motion in the UKA group was significantly bigger than TKA group (P<0.05); The rate of pain relieve, blood loss, hemoglobin decrease on 3 day after operation and hospitalization stay in the UKA group were all significantly better than TKA group ( P<0.05) . Conclusion The short-term results of unicondylar knee arthroplasty and total knee arthroplasty for the treatment of knee osteoarthritis are similar. However, the unicondylar knee arthroplasty is more beneficial to postoperative recovery with less intraoperative bleeding and shorter hospital stay.