Osteoarthritis of the knee is a common disease that occurs in middle-aged and elderly people, more often in women than men. Its clinical manifestations mainly include knee pain, recurrent swelling and joint deformity, which can seriously affect daily work and life when symptoms are severe. With the advances in the development of arthroscopic devices, the in-depth understanding of the pathological changes of knee osteoarthritis and the accumulation of experience in arthroscopic surgery, arthroscopic knee cleanup surgery has become a common method for treating knee osteoarthritis. Compared with osteotomy and total knee replacement, it has the advantages of less trauma, faster recovery, repeatability, and fewer complications. Specific surgical methods are as follows: 1) joint cavity irrigation: studies have shown that the removal of intra-articular debris, proteolytic products, collagenase, gelatinase, matrix enzymes, inflammatory factors, calcified pyrophosphate crystals, etc., can lead to pain relief; 2) cartilage planing and shaping: arthroscopic planing of sclerotic bone with electric instruments, with the aim of stimulating the regeneration and repair of fibrocartilage in the femoral condyle; 3) drilling: elevated intraosseous pressure in the knee joint is One of the causative factors, through drilling can reduce intraosseous pressure and can stimulate the repair of cartilage; 4, joint cleaning: joint cleaning is a group of methods used for the pathological changes of OA, currently the most widely used in clinical practice, including limited removal of hypertrophic synovial, meniscal repair, cartilage debris and free body removal, removal of hyperplasia in the joint cavity, etc. In conclusion, arthroscopic treatment of OA has been widely adopted by clinicians, and most recent clinical observations have yielded satisfactory results. As an important component of OA, arthroscopic treatment of patellofemoral arthritis is receiving more and more clinical attention and has obvious efficacy.