Objective To summarize the research progress of CD90 protein. Methods The demestic and international published literatures related to CD90 protein in recent years were collected and reviewed. Results CD90 protein was involved in the cell-cell and cell-cytoplasm function. CD90 protein could promote axons growth and neural regeneration， and could induce apoptosis of thymus gland cells and stromal cells. CD90 protein participated in cell adhesion， extravasation and transfer， and the regulation of fibrosis. CD90 protein was a potential marker for cancer stem cells. Conclusion CD90 protein is very important in development of many diseases， and can provide a new molecular target to diagnose and treat neoplasms.