Objective:To study the role of Jagged1 and Notch signaling pathway played in the differentiation and proliferation of RAW 264.7 cells.Methods: RAW 264.7 cells were divided into three groups to culture:The control group:RAW 264.7 cells were threated with culture and RANKL.The Jagged1 group:RAW 264.7 cells were threated with recombinant protein Jagged 1 besides the control group.The DAPT group:RAW 264.7 cells were threated with DAPT besides the Jagged 1 group.The mRNA expression of osteoclast markers(TRAP,CK,CTR) and Notch key target genes (HES-1 and HEY-1) were measured by real-time PCR.The formation of osteoclast , bone resorption , Notch expression and proliferation of RAW 264.7 cells were detected by TRAP staining , scanning electron microscope ,immunofluorescence and cell counting kit-8 ( CCK-8 ).Results: TRAP, CK, CTR , HES-1 and HEY-1 mRNA expression were significantly higher than the control group and DAPT group in Jadded 1 group ( P<0.05 ).TRAP+cell count ,osteolytic area was significantly increased in Jagged 1 group compared with control and DAPT group , and no significant difference observed between the last two groups.Immunofluorescence results showed high expression of N ICD in cell membrane and cytoplasm in all groups and additionally expressed in nucleus in Jadded 1 group.Cell proliferation was inhibited in Jagged 1 group also ( P<0.05 ).Conclusion:Jagged1 promotes RAW264.7 cells osteoclast differentiation and inhibits proliferation by activating Notch signaling pathway .