Objective To explore the incidence and severity of symptoms of the lung cancer patients undergoing concurrent chemoradiation therapy, and reveal the influence of symptom clusters on the patients’ daily activities. Method From December 2016 to June 2017, a total of 150 patients with lung cancer who underwent concurrent chemoradiation therapy were investigated by using M. D. Anderson Symptom Inventory of Chinese Version and the revised lung cancer module. Results For the patients during the period of concurrent chemoradiation therapy, the symptoms with severity score >5 were fatigue, nausea, poor appetite, cough, distress, disturbed sleep, vomiting, expectoration, and grief; the symptoms with incidence >80% were fatigue, nausea, disturbed sleep, poor appetite, grief, and cough. Joy of life (87.33%), emotion (74.38%), and work (72.67%) were the top three in terms of high incidence of symptom distress. Exploratry factor analysis revealed 4 major symptom clusters, which were fatigue-related symptom cluster, gastrointestinal symptom cluster, emotion symptom cluster, and respiratory symptom cluster. Conclusions During the period of concurrent chemoradiation therapy, lung cancer patients suffer from multiple symptom clusters. Medical staff should assess symptoms timely, and provide effective interventions, to improve the patients’ quality of life.