Objective To Compare the clinical efficacy of single knee arthroplasty(UKA) and total knee arthroplasty(TKA) with posterior cruciate ligament(PCL) preservation.Methods 102 patients who underwent knee joint replacement surgery at Dongguan Traditional Chinese Medicine Hospital from January 2019 to March 2021 was collected.Among them，58 patients underwent knee joint single condyle replacement surgery and 44 patients underwent posterior cruciate ligament preserving total knee joint replacement surgery.There were 8 males and 50 females in the UKA group.The age ranges from 52 to 83 years，with an average of (66.13±6.67)years old.There were 6 males and 38 females in the TKA group.The age ranges from 54 to 81 years，with an average of (67.79±6.74)years.We evaluated clinical efficacy by comparing patients’ perioperative conditions，joint function scores，and changes in lower limb strength lines.Results Both groups of patients were followed up.The TKA group was followed up for 12 to 21 months，with an average of (15.72±1.89)months，while the UKA group was followed up for 12 to 19 months，with an average of (15.34±1.68)months.The UKA group was superior to the TKA group in terms of surgical time，incision length，hemoglobin decrease，length of hospital stay，first landing time，and abducting time (P＜0.05).One year after surgery，there was no statistically significant difference in VAS between the two groups (P＞0.05)；The UKA group outperformed the TKA group in terms of range of motion(ROM)，Western Ontario and McMaster Universities(WOMAC) knee function score，and hospital for special surgery(HSS) knee score，with statistically significant differences (P＜0.05).The correction ability of the medial proximal tibial angle(MPTA)，mechanical lateral distal femoral angle(mLDFA)，and posterior distal femoral angle(PDFA) in the UKA group was similar (P＞0.05)，while the correction ability of the femorotibial angle(FTA) in the UKA group was slightly inferior to that in the TKA group.Conclusion The UKA group has comparable ability to correct lower limb force lines compared to the TKA group，and has the advantages of better improvement of knee joint function，less trauma，shorter hospital stay，and faster landing.It is recommended to prioritize UKA medial condylar replacement while strictly grasping the surgical indications，in order to improve patient satisfaction after knee joint replacement surgery.