Objective To explore the application value of MRI in the evaluation of nedaplatin combined with fluorouracil induction chemotherapy in the treatment of locally advanced nasopharyngeal carcinoma. Methods 60 patients with advanced nasopharyngeal carcinoma admitted in our hospital from May 2014 to May 2016 were selected for the study and treated with nedaplatin combined with fluorouracil induction chemotherapy. MRI examination was performed before and after treatment. The total effective rate after treatment was calculated and the slopes of the MRI curve were compared between the patients with recurrence and fibrosis. Results After chemotherapy, the tumor area was significantly smaller than that before chemotherapy and the boundary was clearer than before. What's more, low signal in T1W1, high signal in T2W1, low signal in DWI and uneven enhancement shown in the DCE-MRI scan were expressed after chemotherapy. There were 31 cases of CR, 24 cases of PR, 2 cases of SD, 3 cases of PD and the effective rate was 91.67%. The average area of tumor was (5.23±3.42)cm2 before chemotherapy and (1.25±1.67)cm2 after chemotherapy, and the tumor regression rate after chemotherapy was 76.11%. After half a year follow-up, there were 13 cases of recurrence and 47 cases of fibrosis. And the slope was (19.23±9.27) in the recurrence group and (4.53±1.57) in the fibrosis group shown by the DCE-MRI scan, and the slope of the fibrosis group was significantly lower than that of the recurrence group, therefore the difference was statistically significant(t=10.32, P<0.05). Conclusion MRI can clearly show the tumor size, shape and border, and has a high sensitivity to the tumor signals and biological changes in patients with nasopharyngeal carcinoma, and has important application values in the efficacy evaluation after chemotherapy and the identification of recurrence and fibrosis tissues.