Aim and Background: Due to the high rates of diabetes in Iran and the world, as well as due to the lower side effects of medicinal plants in comparison with chemical and industrial drugs, this study investigated the effect of the active ingredient of Mary Magenta (Silybum marianum) on the expression of the Neuro D1 gene, one of the genes of the genes And the restoration of beta and alpha pancreatic cells is also a study of blood glucagon levels in rats. Material and methods: 42 male Wistar rats were randomly selected and divided into seven groups of six. Diabetic rats received different doses of silymarin and metformin every other day for 1-3 days and after 40 days anesthetized with chloroform. After blood sampling, the serum glucagon level was measured by glucagon assay kit ELISA Then, the stages of the description and operation of pancreatic tissue extraction and extraction of RNA and cDNA were performed and expression analysis was performed using Real Time RT-PCR technique. Results: The results of this study showed that STZ causes the destruction of pancreatic tissue and type 1 diabetes. Application of Silymarin improved diabetes and decreased glucose levels and increased serum glucagon levels in rats receiving different doses of silymarin compared to the control group (diabetic). Also, the expression level of NeuroD1 gene increased significantly compared to the GAPDH gene (reference gene). Conclusion: The expression of NeuroD1 gene in STZ-induced diabetic rats showed a significant increase (P-Value = 0. 000), which resulted in improved pancreatic tissue and decreased blood glucose and increased rats and muscle mass by regenerating cells The pancreatic alpha, as well as the binding to the promoter of the glucagon gene, enhance the expression of this gene.