Objective:To research whether G-protein coupled receptor kinase-interacting protein 1(GIT1) regulates the differentiation of bone marrow cells into osteoclasts through Notch signaling pathway. Methods:Bone marrow cells, which obtained from eight GIT1+/+ and eight GIT1-/- mice of 8-week-old, were isolated and cultured,then were induced to osteoclast differentiation. The tartrate-resistant acid phosphatase (TRAP) activity was detected to evaluate the osteoclast differentiation at day 4 and 7. Real-time RT-PCR were performed to detect the expression of cathepsin K (CTSK),calcitionin receptor(CTR),matrix metalloproteinase 9 (MMP9) and Notch signaling pathway at day 4 and 7. Results: The size,number and density of osteoclasts were lower in the GIT1 gene knockout group compared with the wild type group. The expression of CTSK,CTR and MMP9 in GIT1 gene knockout group was significantly lower than that of the wild type group (P < 0.05). However,The expression of Jagged1,Notch2 and Hes1 in the GIT1 gene knockout group was significantly higher than that of the wild type group (P < 0.05). Conclusion:The deficiency of GIT1 inhibited the differentiation of bone marrow cells into osteoclasts through upregulating Notch signaling pathway.