Abstract： Objective To explore diagnostic value of MR perfusion weighted imaging(PWI)on complications and tumor recurrence in hypopharyngeal and laryngeal cancer after operation and radiotherapy. Methods MR PWI was performed in 31 patients with hypopharyngeal and laryngeal cancer who suffer from tumor recurrence, granulation or infection after operation and radiotherapy. Blood flow (BF), blood volume(BV), mean transit time(MTT) and time to peak (TTP) values were measured in the lesions. Analysis of variance and pair-wise comparison of q test were used for statistical analysis. Results Eleven cases with tumor recurrence,11 case with granulation tissues, 9 cases with infection were confirmed by pathological examinations. Average BF, BV, MTT and TTP values of recurrent tumors were (145.1 ± 29.3)ml · 100 g-1 · min-1,(14.2 ± 3.2)ml · 100 g-1,(5.4 ± 0.6)s,(13.7 ± 1.3)s respectively;Average BF, BV MTT and TTP values of granulation tissues were(109.1±27.4)ml·100 g-1·min-1,(11.1±1.7)ml·100 g-1,(7.7±1.0)s, (19.8 ± 2.1)s respectively;Average BF, BV, MTT and TTP values of infectious tissues were(86.9 ± 7.7)ml · 100 g-1·min-1,(8.8±1.0)ml·100 g-1,(8.0±0.9)s,(19.7±1.3)s respectively. Average BF and BV values of the recurrent tumors group were higher than those of the granulation(q=4.89, 4.64 respectively,P<0.01)and infection group(q=7.52,7.71 respectively,P<0.01)respectively. Average BV values of granulation group was higher than that of the infection group(q=3.31,P<0.05), Average MTT and TTP values of recurrent tumor group were lower than those of the granulation (q=9.38, 12.48 respectively,P<0.01)and infection group(q=9.77, 11.53 respectively,P<0.05). There were no significant difference in average BF, MTT and TTP between the granulation and infection group. Conclusion MR PWI can be helpful in the diagnosis of complications and tumor recurrence in hypopharyngeal and laryngeal cancer after operation and&nbsp;radiotherapy.