Abstract: Objective To improve the diagnostic accuracy of focal nodular hyperplasia (FNH) of the liver by analyzing its findings by helical CT multiphase scanning. Methods A retrospective analysis of the plain scanning and dynamic enhanced scanning helical CT findings was conducted in 20 pathologically verified FNH cases. Results On plain CT scans, the FNH lesions appeared as hetrogeneous or homogeneous hypodense areas. In the arterial phase, all lesions were vigorously and homogeneously enhanced except for the central scar and lesions in 1 case. In 6 cases, tortuous and dilated arteries were seen in the center or peripheral of the lesion in 16-slice spiral CT. In the portal venous phase and delayed phase, the lesions were slightly hyperdense, isodense or slightly hypodense. Central scar was found in 13 cases, which showed late enhancement. Atypical findings included multinodular FNH in 2 cases, pseudocapsular enhancement in 2 cases, calcification in 1 case, and necrosis in 1 case. Conclusion Multiphase helical CT scanning can fully display the pathological and blood supply characteristics of FNH and improve the differentiation of FNH from other malignant hypervascular tumors.