Knee osteoarthritis (KOA) is a common chronic degenerative disease of cartilage, which often occurs in middle-aged and elderly patients. It can cause joint swelling, pain and limited movement. With the aging population gradually increasing in China, the prevalence of KOA is also increasing, imposing burdens on patients, families and society. At present, the clinical treatment methods for KOA mainly include physical exercise therapy, non-steroidal analgesic drug therapy, intra-articular hormone injection therapy and surgical treatment, which can improve symptoms and reduce pain but cannot effectively cure KOA. With the development of medicine, platelet-rich plasma (PRP) therapy, as a new treatment method, has the effects of nerve repair and pain relief, and has become a new choice for the treatment of KOA. This article reviews the application of PRP in KOA, so as to provide a new perspective for clinical treatment of knee osteoarthritis KOA.