Suppressor of cytokine signaling (SOCS) is a new family of proteins produced in cells. It may play an important role in classic negative feedback loop to regulate cytokine signal transduction. SOCS-1 was observed and confirmed firstly. Expression of SOCS-1 can inhibit cytokine signal transduction of some cytokines, such as IL-6, LIF, OSM, INF-gamma, GH, and so on, many immune responses are regulated by them in vivo. Abnormal expression of SOCS-1 is closely related to some human diseases. It plays an important role in the development of leukemia, rheumatoid arthritis, liver cirrhosis and liver cancer. In this review, the advances of research on the relationship between SOCS-1 and cytokine, and its correlation with some diseases were summarized.