Objective To analyze the changes of the apparent diffusion coefficient and the signal intensity of portal vein in patients with primary hepatocellular carcinoma (HCC) retrospectively, and to explore the effect of multimode MRI on the efficacy of interventional therapy for primary liver cancer. Methods A total of 50 patients with primary hepatocellular carcinoma who were treated in our hospital from March 2014 to March 2015 were enrolled in this study. the patients underwent nuclear magnetic resonance scan before, 1 month after treatment and 6 months after treatment,. Comparison of the apparent diffusion coefficient and the enhancement of signal intensity in the portal vein before and after treatment were evaluated. Results The apparent diffusion coefficient was (1.23±0.37)×10-3mm2 before the treatment of HCC, and the mean value was (1.93±0.53)×10-3mm2 after treatment. There was significant difference between the two groups (P<0.05) The mean signal intensity of the portal vein was (59±19)% and (47±21)% after treatment, which was significantly lower than that before treatment (P <0.05). 6 months after treatment, the efficacy of the lesion was classified, a total of 81 lesions, including some of the relief of 34, stable lesions of 36, the progress of 11 lesions, the use of nonparametric ROC curve analysis found that the efficacy of the table (P<0.05). There is a significant difference between the two groups (P<0.05). Conclusion MRI multimodal study can be used as an indicator of the efficacy and prognosis of HCC after interventional therapy. The effect of the therapy can be predicted by the degree of change of the signal intensity and the enhancement of signal intensity through the apparent diffusion coefficient and portal vein.