Objective To investigate short-term clinical efficacy of autologous leukocyte-poor platelet-rich plasma(LP-PRP)treatment of knee osteoarthritis(KO A).Methods 85 cases of patients with Keligren Lawrence grade Ⅰ-Ⅲ knee os-teoarthritis in Peking University First Hospital Taiyuan Hospital(Taiyuan Central Hospital)from 2022 to 2023 were collect-ed for autologous LP-PRP collection and quality assessment using a blood component separator,and all patients were treated with autologous LP-PRP.The degree and function of knee pain were assessed by visual analog scale(VAS)and knee arthri-tis index scale(WOMAC)at 1,3 and 6 months after injection.Knee MRI was performed after 6 months of treatment,and the MRI imaging changes before and after treatment were compared.Different influencing factors in the treatment results were grouped and analyzed,mainly including platelet concentration in LP-PRP and K-L grading of knee joint.According to the platelet concentration in LP-PRP,it was divided into three grades,which are low concentration[(＜800)×109/L],medium concentration[(800-1 000)×109/L],and high concentration[(＞1 000)× 109/L];According to the K-L grade of the knee joint,the severity of knee osteoarthritis was divided into three grades:Ⅰ、Ⅱ、Ⅲ.Results The VAS and WOMAC scores at 1,3 and 6 months after LP-PRP treatment were significantly lower than those before treatment,and the difference was sta-tistically significant(P＜0.05).There was a statistically significant difference in the therapeutic effect of different levels of platelet concentration,and when the platelet concentration was more than 1 000×109/L,the significant effect was the most obvious(P＜0.05).The therapeutic effect of different levels of platelet concentration was statistically significant(P＜0.05).MRI showed that the articular cartilage signal was significantly improved after treatment.Conclusion Autologous LP-PRP injection into knee cavity for the treatment of KO A has a good short-term clinical effect in relieving knee pain.