Objective To analyze the value of real-time shear wave elastography (SWE) in the quantitative evaluation of fatty liver in obese children, so as to provide more evidence for early diagnosis, intervention and treatment of obese children with fatty liver. Methods From April 2018 to April 2020, a total of 331 obese children who visited the Children and Adolescents Obesity Clinic in the Second Affiliated Hospital of Xi′an Jiaotong University were selected as fatty liver group.Meanwhile, 100 healthy children were selected as control group.Using clinical diagnosis as the reference standard, the shear wave velocity (SWV) and young′s modulus value (EI) of the liver in two groups of children were measured using real-time shear wave elastography, and the difference was compared.ROC curve was then drew to determine the optimal cut-off value for fatty liver in obese children.Additionally, the general data of children were recorded, and the relevant blood biochemical test results were collected to compare the correlation between SWV value, EI value and clinical indicators in children with fatty liver disease. Results There were no statistically significant differences in age, height and alanine amino transferase between obese children and normal children (P>0.05).But the differences in body weight, body mass index(BMI), waist-hip ratio, total cholesterol and serum triglycerides between the two groups were statistically significant (t=3.681, 4.010, 4.587, 3.562, 7.015, P<0.05).The SWV value of the fatty liver group was (1.83±0.24)m/s, significantly higher than that of the control group [(1.01±0.19)m/s].ROC curve indicated that the best diagnostic cut-off point for SWV in obese children with fatty liver was 1.35m/s, the sensitivity and specificity was 0.94 and 0.81, respectively, and the area under the ROC curve was 0.932.The EI value of the fatty liver group was (7.11±0.39)kPa, significantly higher than that in the control group [(5.94±0.26)kPa].ROC curve indicated that the optimal diagnostic cut-off value of EI in obese children with fatty liver was 6.32 kPa, the sensitivity and specificity was 0.96 and 0.72, respectively, and the area under the ROC curve was 0.879.Both SWV and EI values were positively correlated with body weight, and BMI, waist-hip ratio, total cholesterol and serum triglyceride (r_SWV=0.401,0.450,0.488,0.352,0.697; r_EI=0.377,0.463,0.501,0.331,0.611,P<0.05). Conclusion Real-time shear wave elastography can accurately and noninvasively identify the degree of fatty liver in obese children, which is of great significance for the early diagnosis, intervention and treatment of fatty liver in obese children.