Abstract: ObjectiveTo investigate the development trajectory of triglyceride-glucose index （TyG) in a health examination cohort and its correlation with new-onset non-alcoholic fatty liver disease （NAFLD). MethodsA retrospective cohort study was conducted. A total of 2 224 individuals who met the inclusion criteria of the team at the Health Management Center of Emergency General Hospital from January,2012 to December,2022 were retrospectively selected as the sthdy objects. Three TyG index trajectory groups of low,medium and high levels were determined by the group-based trajectory model. The gender,age，systolic blood pressure(SBP),diastolic blood pressure（DBP)，body mass index (BMI)，creatinine （Cr)，uric acid (UA)，total cholesterol (TC)，high density lipoprotein cholesterol (HDL-C)，low density lipoprotein cholesterol(LDL-C)，alanine aminotransferase（ALT)，blood urea nitrogen（Urea)，TyG index and cumulative incidence of NAFLD were compared among the three groups. Coxregression model was used to analyze the onset risk and the risk factors of NAFLD. RCS model was used to analyze the correlation between TyG index and the onset risk of NAFLD.ResultsCompared with the low trajectory group,the baselines HDL-C of the medium and high trajectory groups were significantly lower, and the other indicators were significantly higher （P 8.35，and there was a non-linear correlation between them(P=O.0o8). Conclusion A higher TyG index is associated with an increased risk of NAFLD in the health examination population,and therefore,TyG index may serve as a novel predictor for the incidence of NAFLD.