Objective  To investigate whether the overexpression of neurogenin 3（Ngn3）can promote the induced differentiation of human umbilical  cord mesenchymal stem cells（HUCMSCs）into insulinproducing cells（IPCs）.    Methods  HUCMSCs were isolated and cultured, identified by flow cytometry, and the differentiation potential was identified by adipogenesis and osteogenesis induction. HUCMSCs were induced into IPCs in different stages, including a low glucose induction stage and a high glucose induction stage. The experiment was divided into two groups, the control group was induced by the above scheme, while the experimental group was additionally infected the lentivirus overexpression vector carrying the target gene Ngn3 on the 6th day of the same induction process. After induction, the changes of cell structure were observed by electron microscope; mRNA and protein was collected and Real-time PCR and Western blotting were used to compare the expressions of insulin and musculoaponeurotic fibrosarcoma oncogene homolog A Mafa in the two groups; medium supernatant was collected and C-peptide content was determined by ELISA.   Results  HUCMSCs were successfully isolated with positive expression of CD105 and CD90 and negative expression of CD34 and CD45, which had adipogenic and osteogenic differentiation ability. Then, HUCMSCs were induced into IPCs by stage induction, and the cells expressed Mafa and insulin positively. Ngn3 was overexpressed in the experimental group during the induction. After induction, electron microscopy showed that the cell structure was more mature in the experimental group. The expression levels of insulin and Mafa in the experimental group were significantly higher than those in the control group. During the induction process, the amount of C-peptide secreted by the experimental group was higher than that of the control group.    Conclusion  Lentivirus-mediated Ngn3 overexpression improves the differentiation efficiency of HUCMSCs into IPCs.