【Objective】 To study the effects of gestational diabetes (GDM) on morphological structure of brain tissue and microribonucleotide (miRNA) expression profile in neonatal mice, and to provide a new research target for the prevention and treatment of abnormal neurodevelopment in GDM progeny. 【Methods】 The pregnant mice were divided into model group and control group,each group consisted of 10 mice. The model group mice established a GDM model by injecting streptozotocin to measure fasting blood glucose (FPG) and random blood glucose (GLU) at different times. Successful molded mice were randomly divided into model group A and model group C, and control mice were divided into control group B and control group D, with 5 mice in each group. The newborn mice in groups A and B were used for hippocampal tissue GeneChip detection and brain morphology structure observation, and group C and D newborn mice were used for qRT-PCR detection of hippocampus tissue expression differences to verify the differentially expressed genes of miRANs obtained by GeneChip screening. After giving birth, the neonatal mice were sacrificed by decapitation, and the brain tissue was dissected to observe the overall morphological structure. The structural changes of hippocampus were observed under HE chromogenic microscope. The Agilent mouse miRNA oligonucleotide gene chip was used to detect the miRNA expression profile of mouse hippocampus, screen differential miRNAs and predict their target genes, and conduct GO analysis and signal transduction pathway analysis of target genes. The relative expression levels of the screened miRNAs were verified by qRT-PCR. 【Results】 Compared with the control group, the GLU increased significantly from the 3rd day after drug administration in the model group (P<0.01). Macroscopic observation of control group B mice had normal brain morphology and structure, smooth appearance, clear gyrus, close arrangement of hippocampus cell structure, uniform staining and complete structure; in model group A, the number of hippocampus cells decreased, loose arrangement and deep staining. In the initial screen of miRNA microarray, there were 11 differentially expressed miRNAs between control and model groups, all of which were downregulated miRNAs, including let-7b-5p、miR-130b-3p、miR-181c-5p、miR-181d-5p、miR-3099-3p、miR-3470a、miR-3473a、miR-3473b、miR-500-3p、miR-532-5p、miR-7047-5p(P<0.05). Two miRNAs (miR-3473b, miR-7047-75p) and 5 target genes (MAPK3, MAPK11, MAPK14, CALM3, AKT3). The relative expression of miR-3473b and miR-7047-5p in model group C were lower than that in control group D (t=19.13 and 6.24, P<0.05), and the validation results were consistent with the microarray test results. 【Conclusion】 Compared with the offspring of normal pregnant mice, GDM offspring mice have abnormal development of brain structure and damage of hippocampal nerve cells, and there are a large number of abnormal expression of miRNAs in hippocampal tissue. Differentially expressed miRNAs can be used as research targets for prevention and treatment of GDM offspring neurodevelopmental abnormalities.