Abstract: Osteoarthritis is a chronic degenerative disease in the joints. The prevalence of OA is the highest in all rheumatic disease, which is a challenge being faced by the rheumatologists and orthopedic surgeons. It is particularly vital to study the risk factors and underlying mechanisms of OA. So far, clinical research of OA in China is largely using the cross-sectional design, which cannot explain the possible causal relationship. In this article, we will review the literatures of major cohort studies performed internationally, and elucidate their research design, methods, findings and their respective characteristics. This will help us to recognize the importance of cohort studies in OA research and to design appropriate cohort studeis in the near future.