Objective: To explore the mechanism of action of hepatic leukemia factor (HLF) in diabetes mellitus and to construct a conditional animal model of mice with islet β ⁃cell⁃specific HLF gene knockout. Methods: At the cellular level , the effects of HLF inhibition or overexpression on the proliferation of MIN6 cells was verified by the CCK⁃8 assay. The effects of HLF inhibition or overexpression were detected at the mRNA level and protein level by Cre + / - mice (C57BL/6J) to obtain offspring mice. The genotypes of the mice were identified by the PCR method.The differences in the expression levels of the HLF gene at the mRNA and protein levels in islet β ⁃cell knockout mice (HLFflox/flox Cre + / - ) and control mice (HLFflox/flox ) were detected by RT⁃qPCR technology and Western blot technology to verify the knockout effect. At the same time , the islet tissues of the mice in two groups were taken to make paraffin sections and analyzed by hematoxylin⁃eosin (HE) staining. Results: HLF gene inhibition or overex⁃pression had no significant effect on the proliferation of MIN6 cells. When the HLF gene was inhibited in MIN6 cells , the mRNA expression level decreased by 74% compared with the control group , and the protein expression level decreased by 60% compared with the control group. After overexpressing the HLF gene , the mRNA expres⁃sion level was 2. 13 times compared with that of the control group , and the protein expression level was 1. 8 times compared with that of the control group. The mRNA expression level of the HLF gene in the knockout mice de⁃creased by 89% compared with the control group , and the protein expression level decreased by 65% compared with the control group. The results of HE staining showed that there was no significant difference in the cell mor⁃phology in the islet tissues between the knockout mice and the control mice. Inhibiting HLF increased the glycogen content in MIN6 cells by approximately 20% . Conclusion The HLF gene knockout mice are successfully con⁃structed , providing an animal model for studying the role of HLF in the pathogenesis of diabetes mellitus.