Objective To compare the diagnostic value of contrast-enhanced ultrasonography and multi-phase dynamic contrast-enhanced CT in patients with hepatitis B combined with primary liver cancer. Methods The data of 56 patients with hepatitis B and primary liver cancer who were treated in our hospital from May 2015 to May 2018 were retrospectively analyzed.The pathological examination results were used as the gold standard to compare the diagnostic rates of different examination methods for primary liver cancer, and to summarize the imaging findings of primary liver cancer. Results The coincidence rate (92.86%), sensitivity (96.43%) and specificity (89.29%) of multi-phase dynamic contrast-enhanced CT in the diagnosis of primary liver cancer were significantly higher than the coincidence rate (71.43%), sensitivity (75.00%) and specificity (57.14%) in contrast-enhanced ultrasonography(P<0.05). Contrast-enhanced ultrasonography showed 82 lesions with high enhancement in the arterial phase, and 48 lesions with low enhancement in the portal venous phase and delayed phase. In the multi-stage dynamic contrast-enhanced CT, 58 lesions showed smooth edge of the capsule and obvious ring enhancement, and the other 18 lesions were characterized by envelope with incomplete enhancement and fuzzy edge.All lesions showed a high-density enhancement in the arterial phase, a reduced enhancement in the portal phase, and a fast-forward and fast-out mode with enhancement fading in the delayed phase. Conclusion The diagnostic accuracy of multi-phase dynamic contrast-enhanced CT in diagnosis of hepatitis B combined with primary liver cancer was higher than that of contrast-enhanced ultrasonography, Multiphase dynamic enhanced CT can more clearly show the type, size and location of the lesion, which is more beneficial to in clinic diagnose and guide treatment.