Our study demonstrated that upregulation of Pin1 expression increased the phosphorylation of AKT and insulin receptor substrate 1 downstream signaling molecules of the IR‐IGF1R pathway, increased the phosphorylation of GSK‐3β, and concomitantly decreased the phosphorylation of Tau in the hippocampus of diabetic mice, thereby improving the ultrastructural pathology of the hippocampus and further alleviating diabetes‐related cognitive impairment. Here, PIN1 is linked to diabetes mellitus.