Osteoarthritis (OA), as the most common degenerative joint disease, is mainly characterized by destruction and degradation of cartilage, which leads to joint function loss and seriously affects the quality of life of patients. More and more evidences show that in addition to cartilage tissue, the pathological changes of OA involve other tissue system including synovium, bone and subchondral bone. Among that, synovium, an important part of the tissue system, plays an increasingly prominent role in OA. Synovial cells are classified into type A synovial macrophage (SM) and type B synovial fibroblast (FLS), which play different but closely related roles in OA. This article reviews the role of different types of synovial cells in OA, and provides scientific theoretical basis for further understanding the pathogenesis and treatment of OA.