Abstract： Objective　By making use of SPECT radioactive dynamic imaging, to investigate the possibility of quantitative evaluation of salivary gland function of NPC patients who were treated by radiotherapy.Methods　SPECT radioactive dynamic imaging was executed for 63 NPC patients before and after radiotherapy.We utilized ROI sequence software of SPECT for quantitatively evaluating the ingestion-excretion function of salivary gland. Results　The damage rates of the excretion function of parotid gland and submandibular gland of 63 NPC patients after radiotherapy were 19,7,7,4,89 and 22,24,20,12,48,respectively. The damage rates of the ingestion function and excretion function of parotid gland were 51,12,16,6,41 and 19,7,7,4,89,respectively. The damage rates of the ingestion function and excretion function of submandibular gland were 58,8,11,6,41 and 22,24,20,12,48, respectively. There all were obvious difference between them (p<0.005).Conclusions　SPECT radioactive dynamic imaging is a sensitive and useful method in determining the salivary gland function of NPC patients who were treated by radiotherapy. As to salivary gland function damage of NPC patients who were treated by radiotherapy,the parotid gland function damage is primary. And the excretion function damage is more serious than the ingestion function damage of parotid gland or submandibular gland.