Osteoblasts are the most important mechanoreceptive and osteogenic cells.The loss of bone in microgravity is mainly due to the dysfunction of osteoblasts.Research on osteoblast cytology under simulated weightlessness has made great progress in recent years. Current experiments are focusing on the changes in the cellular proliferation,differentiation,apoptosis,function and signal transduction in osteoblasts.This paper reviews the progress of the studies in this field.