Abstract: Objective To study the differentiation of bone marrow mesenchymal stem cells (bMSCs) into insulin-producing cells (IPCs) and the expression of Ngn3 in differentiation of miR-106b-regulated IPCs. Methods The isolated bMSCs were induced to differentiate into IPCs with activin A andβcellulin. Target match relation between miR-106b and Ngn3 was predicted using miRanda and TargetScan respectively, and identified with the dual luciferase report system. Expressions of miR-106b and Ngn3 were detected by RT-PCR during the differentiation of bMSCs into IPCs. Results The IPCs were stained scarlet with DTZ. Immunofluorescence cytochemistry showed expression of insulin. Bioinformatics method demonstrated that miR-106b was well matched with Ngn3. Dual luciferase reporter system revealed that miR-106b bound to the 3'UTR of Ngn3 mRNA could effectively inhibit the expression of Ngn3. RT-PCR displayed that the expression level of miR-106b was negatively related with that of Ngn3 mRNA. Conclusion miR-106b can regulate the expression of Ngn3 during the differentiation of bMSCs into IPCs.