Objective To explore the relationship between CT value of liver-to-spleen ratio and ADC value in the patients with fatty liver, and investigate the feasibility of ADC value in assessing hepatic steatosis grade of nonalcoholic fatty liver disease. Methods Eighty patients were analyzed retrospectively in this study, all the patients were performed CT and MRI examination, including normal group (n=20), mild fatty liver group (n=20), moderate group (n=20) and severe fatty liver group (n=20). The correlation analysis between CT value of liver-to-spleen ratio and ADC value was evaluated, and differences among four groups were also analyzed in this study. P<0.05 was considered as statistical significant difference. Results There was significant positively correlation between CT value of liver-to-spleen ratio and ADC value (r=0.954, P<0.05), and ADC value of liver parenchymal: normal group (1.451±0.123)×10-3mm2 /sec, mild fatty liver (1.341±0.014)×10-3mm2 /sec, moderate fatty liver (1.206±0.007)×10-3mm2 /sec, severe fatty liver (1.040±0.017)×10-3mm2 /sec, there was significant statistical difference among four groups (all P<0.05). Conclusion There was significant positively correlation between CT value of liver-to-spleen ratio and ADC value, ADC value could be available for evaluating hepatic steatosis grade of nonalcoholic fatty liver disease.