Objective To analyze the diagnostic value of quantitative ultrasound attenuation imaging for nonalcoholic fatty liver disease (NAFL) and its relationship with the severity of NAFL. Methods A total of 85 patients with NAFL confirmed in the hospital were enrolled as observation group between January 2018 and June 2021, including 25 cases, 35cases and 25 cases with mild, moderate and severe NAFL. A total of 25 controls with normal liver during the same period were enrolled as control group. Both groups underwent examinations of routine liver ultrasound and quantitative ultrasound attenuation imaging. The general data, lipid metabolism indexes [total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-C)] and controlled attenuation parameters(CAP) were compared between control group and observation group. The stability of measurement values was evaluated by intra-class correlation coefficient (ICC). The correlation between CAP and lipid metabolism indexes, body mass index (BMI) was analyzed by pearson correlation analysis. The diagnostic value of quantitative ultrasound attenuation imaging parameters for different severity of NAFL was analyzed by receiver operating characteristic (ROC) curves. Results In control group and patients with mild, moderate and severe NAFL, BMI, TC and TG were increased, while HDL-C was decreased in turn. BMI, TC and TG in patients with mild, moderate and severe NAFL were higher than those in control group, while HDL-C was lower than that in control group (P<0.05). In control group and patients with mild, moderate and severe NAFL, CAP value was increased in turn. CAP value in patients with mild, moderate and severe NAFL was greater than that in control group (P<0.05). In control group and patients with mild, moderate and severe NAFL, ICC values were all greater than 0.750. The results of pearson correlation analysis showed that CAP was positively correlated with BMI, TC and TG, while negatively correlated with HDL-C (P<0.05). ROC curves analysis showed that AUC values of quantitative ultrasound attenuation imaging parameters in the diagnosis of mild, moderate and severe NAFL were 0.838、0.864and 0.961, respectively (P<0.05). Conclusion quantitative ultrasound attenuation imaging has high diagnostic efficiency, which can quantitatively evaluate the severity of NAFL, and can be applied in clinical differential diagnosis of NAFL and its guidance treatment.