The purpose of our study was to evaluate the diagnostic efficiency of multiple parameters and the combination with PET/MR in tumor differentiation of HNSCC. The patients with clinical suspicion or diagnosis of HNSCC were included and had the PET/MR examination with 18F-FDG PET and multiple MR sequences. The results showed that there was no significant correlation among different parameters. The differences among groups of tumor differentiation were obvious with ADCmean and SUVmean. Finally, our study suggested that the multiple parameters of PET / MR could be complementary in diagnosis of tumor differentiation and the combination can further improve the performance.