This paper introduces the clinical experience of Professor BAI Weijie in treatment of knee osteoarthritis (KOA) using "Liuʹs filiform fire needle technique" and the academic thoughts. Professor BAI Weijie puts forward that the invasion of wind, cold and damp is biao (symptoms) of KOA, the deficiency of liver and kidney is ben (root cause), the core pathogenesis is the imbalance of muscles and bones, and the syndrome differentiation of this disease is based on the theory of meridian sinew region. Two therapeutic features are presented. First, based on the syndrome differentiation based on the theory of meridian sinew region, the foci of lesion is identified to ensure the precise selection of acupoints. Fuxi (BL38), Xiyangguan (GB33) and Xiguan (LR7) are stimulated to regulate meridian sinew, Futu (ST32), Zhibian (BL54) and Juliao (GB29) to relax knotted tendons; Taixi (KI3) and Kunlun (BL60) are combined to nourish yin, benefit kidney, strengthen tendons and bones and relax muscles and tendons and activate collaterals. Besides, the shu-stream points are supplemented to relieve joint pain. Second, "Liuʹs filiform fire needle technique" is used to promote meridian circulation, activate meridian qi, enhance qi and blood flow and eliminate pathogens by fire needling, deep inserting, swift inserting and other essential skills. The therapeutic principle emphasizes the simplicity in acupoint selection, specificity in needling techniques and targeting treatment, providing a distinctive clinical approach of acupuncture-moxibustion of TCM to the treatment of KOA.