To investigate the effect of baicalin on osteogenic differentiation of stem cells from human apical papilla(SCAPs).The third-passage SCAPs with stable passage ability were selected. After culturing for 24 hours in a medium containing 0, 10, 20, 50, 100 μmol/L of baicalin, cell viability in each group was measured by live/dead fluorescence staining. Then the SCAPs were divided into normal medium group(DMEM) and osteogenic induction medium group(ODM), and the experimental groups were further divided into 5 subgroups according to different concentrations of baicalin, i.e. 0, 10, 20, 50 and 100 μmol/L. Alkaline phosphatase(ALP) staining and ALP quantitative assay were used to detect the effects of different concentrations of baicalin on early osteogenic differentiation of SCAPs for 7 and 14 days; the effect of different concentrations of baicalin on osteogenic mineralization of SCAPs was determined by alizarin red staining after 21 days of culturing. MTT assay was used to detect the effects of baicalin at different concentrations on the growth of SCAPs. SPSS 20.0 software package was used for statistical analysis of the data.The results of live/dead cell fluorescence staining showed that SCAPs were vigorous after treatment in each concentration group, but when the concentration of baicalin was higher than 50 μmol/L, the number of dead cell increased. ALP quantitative results showed that ALP activity in the 20 μmol/L concentration group was significantly higher than that in the control group on the 14th day after induced differentiation in ODM group (P<0.05), and ALP activity in 100 μmol/L concentration group was significantly lower than that in the control group(P<0.05). After 14 days of DMEM culture, ALP activity of 20 μmol/L group was also significantly higher than that of the control group(P<0.05). Quantitative analysis of alizarin red showed that the A value of the 100 μmol/L group was significantly lower than the control group in ODM. 20 μmol/L baicalin was the optimum concentration to promote growth of SCAPs.Baicalin with a concentration higher than 50 μmol/L can significantly inhibit osteogenic differentiation of SCAPs, while low concentration of baicalin, especially 20 μmol/L of baicalin, has a promoting effect on SCAPs osteogenesis differentiation and proliferation.