The primary cultured PDLSCs were isolated and induced osteogenic differentiation. Then the PDLSCs were collected 0， 7 and 14 d after osteogenic differentiation. The expression levels of alkaline phosphatase （ALP）， Runt-related transcription factor 2 （Runx2）， and osteocalcin （OCN） mRNA in the PDLSCs were detected by Real-time fluorescence quantitative PCR（RT-qPCR） method.The expression level of a disintegrin and metalloprotease 10（ADAM10） protein in the PDLSCs was detected by Western blotting method. The PDLSCs were divided into blank control group， vector group，and miR-34a over-expression group. The expression levels of miR-34a in the PDLSCs in various groups were detected by RT-qPCR method， the targeted relationship between miR-34a and ADAM10 genes was verified by dual luciferase report system， and the expression levels of ADAM10 protein in the PDLSCs in various groups were detected by Western blotting method. After the PDLSCs were differentiated by osteogenesis， the formations of mineralized nodules in the PDLSCs in various groups were observed by Alizarin red staining， the expression levels of ALP， Runx2， and OCN mRNA in the PDLSCs in various groups were detected by RT-qPCR method， the ALP activities in the PDLSCs in various groups were detected by colorimetric method， the expression levels of Notch1， Notch intracellular domain （NICD）， and Hes1 proteins in the PDLSCs in various groups were detected by Western blotting method.

Compared with 0 d after osteogenic differentiation， the expression level of miR-34a and the expression levels of ALP， Runx2 and OCN mRNA in the PDLSCs at 7 and 14 d after osteogenic differentiation were gradually increased （P<0.05）， while the expression levels of ADAM10 protein were gradually decreased（P<0.05）.Compared with blank control group and vector group， the expression level of miR-34a in miR-34a over-expression group was significantly increased（P<0.05），while the expression level of ADAM10 protein was significantly decreased（P<0.05）. The results of dual luciferase reporter gene system showed that ADAM10 was a target gene of miR-34a in the PDLSCs. Compared with blank control group and vector group， the formation amount of calcified nodules， the ALP activity， and the expression levels of ALP， Runx2， and OCN mRNA in the PDLSCs in miR-34a over-expression group were significantly increased（P<0.05）， while the expression levels of Notch1， NICD， and Hes1 proteins were significantly decreased（P<0.05）.

Over-expression of miR-34a can inhibit the activity of Notch signaling pathway by targeting down-regulation of ADAM10， thus promote the osteogenic differentiation of the PDLSCs.