Abstract:【Objective】To investigate the level and significance of silent information regulator 7 (SIRT7) in peripheral blood mononuclear cells of patients with non-alcoholic fatty liver disease (NAFLD). 【Methods】A total of 205 patients with NAFLD (the NAFLD group) were selected as the research subjects from three hospitals.Healthy volunteers who participated in the health examination at the same time were selected as the control group (n=100). Ficoll density gradient centrifugation was used to isolate mononuclear cells in peripheral blood; Western blot was used to detect the expression level of SIRT7 in mononuclear cells. The relationship between SIRT7 and the severity of NAFLD was analyzed. 【Results】The expression level of SIRT7 in the NAFLD group was lower than that in control group,the difference was statistically significant (P<0.05). With the aggravation of NAFLD,the expression level of SIRT7 gradually decreased. The area under ROC curve,sensitivity and specificity of SIRT7 in the diagnosis of moderate and severe NAFLD were 0.890,75.61% and 87.80%,respectively. Logistic regression analysis showed that FPG,TC,TG,ALT,AST,and SIRT7 were all independent risk factors for progression to moderate and severe NAFLD (P<0.05). The predicted curve constructed by FPG,TC,TG,ALT,AST,and SIRT7 had a high degree of coincidence between the fit curve of the nomogram model and the ideal curve with a C-index of 0.963. 【Conclusion】The low expression level of SIRT7 in peripheral blood mononuclear cells of NAFLD patients indicates that the disease is serious. The nomogram models constructed by FPG,TC,TG,ALT,AST,and SIRT7 have high discrimination and precision,and can effectively judge moderate and severe NAFLD.