Our result showed that diabetes was successfully induced by feeding with HFHGD and combined with streptozotocin intraperitoneal injection in rats, and the β cells in the pancreases of the diabetic rats were damaged, accompanied by a higher content of MDA, higher caspase-3 activity, and lower SOD, CAT, and Bcl-2 levels in the pancreatic tissue, which confirmed that the pancreases of the rats were insulted by oxidative stress. The gene discussed is CASP3; the disease is diabetes mellitus.