Abstract： Objective To investigate the tendency of quality of life in patients with nasopharyngeal carcinoma (NPC) treated with conventional radiotherapy. Methods Quality of life in NPC patients was assessed using FACT-H&N and NPC-QOL Patients were divided into nine groups according to the treatment period :before treatment group, 0 -20 Gy group, 20 -50 Gy group, > 50 Gy group, 0 -6 months after treatment group, 6 - 12 mouths group, 1 -2 years group, 2 -3 years group and 3 -5 years group. Scores of FACT-H&N and NPC-QOL were compared between the either two groups. Results 450 NPC patients were assessed. The total score of FACT-H&N decreased during the treatment and then increased six months after the treatment. The tendencies of physical and functional well-being were similar. The social/family and emotional well-being did not change significantly along with the treatment but the scores of head and neck well-being and NPC-QOL decreased obviously. Xerotomia was aggravated from the initiation of treatment and became the most severe at 6 - 12 months after treatment. 50% - 60% of the patients with disease-free reported severe xerotomia at 3 -5 years after radiotherapy. Incidence of severe trismus increased up to 14% at 3 -5 years after treatment. Conclusions Quality of life of NPC patients with conventional radiotherapy deteriorates during the treatment period, but recovers to the normal level six months after the treatment. Xerotomia and trismus can affect the quality of life of NPC patients.