Objective Cerebral and cervical anatomy structure is complex, rich blood supply and various organs, single mode imaging techniques met challenges in clinical diagnosis and differential diagnosis. This research adopts the 18F FDG PET/CT in combination with MRI high b values DWI imaging of head and neck cancer clinical diagnosis can efficiency were studied. Methods A total of 27cases of clinical diagnosis with head and neck cancer patients accepted 18F FDG PET/CT in combination with MRI (high b DWI) imaging scan. PET/CT scan first, and then to MR conventional sequence and multi b scan. Respectively in the workstation calculation of 18F FDG PET/CT lesions standard perturbation values (standardized uptake value, SUV) with single index (0,1000s/mm2 ) and multiple index model (small b 0-200,middle b 300-1500 and high b, 1700-4500 s/mm2 ) a water molecule diffusion imaging apparent diffusion coefficient (ADC). Results 18F FDG PET/CT and routine MRI scanning sequences were found in patients with head and neck lesions. Visual detection head and neck when b is greater than 3000 s/mm2 benign lesions DWI lesions on signal can have disappeared, and malignant lesions are present high signal. SUV maximum and average have significant statistical difference between benign and malignant lesions(P<0.03), and the number of b scan only high b values exist significant difference(P<0.02). No significant correlations were found between SUV and b value of ADC values(P<0.47). Conclusion The high value of DWI imaging technology can b can help of 18F FDG PET/CT intake in the identification of benign and malignant lesions.