Objective To improve the body image and emotional state of patients undergoing radiotherapy after head and neck cancer surgery. Methods According to the admission time, 100 patients with radiotherapy after head and neck cancer surgery were divided into control group (50 cases) and intervention group (50 cases).The control group received routine nursing and psychological intervention, while the intervention group received positive psychological intervention based on PERMA theory on the basis of routine nursing.The patient′s body image, positive and negative emotions of the two groups were assessed and compared before the intervention, at the completion of the intervention, and one month after the intervention. Results A total of 47 cases in the control group and 49 cases in the intervention group completed this study.The total score and each dimension scores of body image in the intervention group at the completion of the intervention and one month after the intervention were significantly lower than those in the control group (all P＜0.05).The positive emotion score of the intervention group at the completion of the intervention and one month after the intervention was significantly higher than that of the control group in the same period, and the negative emotion score in the intervention group at one month after the intervention was significantly lower than that of the control group in the same period (all P＜0.05). Conclusion Positive psychological intervention based on PERMA theory can improve the body image level and emotional state of patients undergoing radiotherapy after head and neck tumor surgery, and promote their physical and mental health.