Abstract: Objective：To investigate the influence of bone morphogenetic protein-2(BMP-2) on osteogenic differentiation of human inflammatory dental pulp stem cells(DPSCs-IPs) in vitro. Methods：Passage 3 cells dental pulp stem cells from inflamed teeth in medium with or without osteogenic matter. According to whether 100 μg/L BMP-2 was added they were divided into four groups: group 1，DPSCs-IPs culturing with 100 μg/L BMP-2 and osteogenic medium containing; group 2, DPSCs-IPs culturing with 100 μg/L BMP-2 but without osteogenic medium containing; group 3, DPSCs-IPs culturing without 100 μg/L BMP-2 but with osteogenic medium containing; group 4, DPSCs-IPs culturing without 100 μg/L BMP-2 and osteogenic medium containing. After one week of their culture in nonosteogenic condition, we used Trichrome to stain the secretion of collagen matrix, and compared the difference of osteogenic differentiation between them. Real-time RT-PCR was used to test the expression of COL-ⅠmRNA. Three weeks after their culture in osteogenic condition, the cell differentiation was examined by von Kossa staining. Real-time RT-PCR was used to test nuclear transcription factor Nanog, Oct4, SOX2 and osteogenesis related molecules ALP, OCN, BSP, CEMP-1 and COL-Ⅰ gene expression. Results：One week later, Trichrome staining matrix secretion of DPSCs-IPs with BMP-2 group is more obvious than the control group in the nonosteogenic medium. Real-time RT-PCR tests showed that expression of COL-ⅠmRNA increased (P<0.05). The results suggested that BMP-2 could induce DPSCs-IPs deposit more collagen matrix; 3 weeks later, more mineralized matrix secretion of DPSCs-IPs can be observed in the osteogenic medium. In addition, real-time RT-PCR tests showed that experimental group cells express more Nanog, Oct4 and SOX2. And the osteogenesis related molecules ALP, OCN, BSP, CEMP-1 and COL-Ⅰ expression increased significantly compared with the control group (P<0.05). Conclusions：BMP-2 can promote osteogenic differentiation of human inflammatory dental pulp stem cells in vitro in osteogenic condition.