Objective To summarize the characteristics of low echo lesions by ultrasound findings in fat-ty liver,using real -time contrast -enhanced ultrasonography ( CEUS) for differential diagnosis .Methods The study was examed in 128 cases low echo lesions of fatty liver by using CEUS ,the malignant and the highly suspec-ted malignant and part of the benign lesions (in all the 52 cases)were punctured by ultrasound guided biopsy ,the rest of the 76 cases was confirmed benign by clinical comprehensive diagnosis ,were compared to the characteris-tics about ultrasound and contrast -enhanced ultrasound image and reviewed regular follow -up.We calculated the sensitivity,specificity,youden index and the area under the ROC curve by contrast -enhanced ultrasonography and ultrasound and apply for Kappa test for reliability analysis to contrast -enhanced ultrasonography and ultra-sound.Results There were 23 malignant lesions and 105 benign lesions in total of 128 patients.The sensitivity, specificity,youden index and the area under the ROC curve by contrast -enhanced ultrasonography and ultra-sound were 95.65%,98.10%,93.75% and 87.00%,91.43%,84.43%respectively.Compared contrast -en-hanced ultrasound examination diagnosis of low echo lesions in fatty liver with the clinical diagnosis performed good reliability(Kappa=0.922,P=0.045).Conclusion We should pay attention to low echo lesions in the fatty liver.contrast-enhanced ultrasound can effectively identify low echo lesions in the fatty liver ,and identify benign and malignant lesions in the liver ,and improve obviously the accuracy of diagnosis ,and reduce the misdi-agnosis rate.