Abstract: Objective To investigate the degree of psychological distress before radiotherapy in patients with lung cancer, and analyze the related factors of distress for providing basis of clinical individual psychological intervention strategies. Methods Through the general information and psychological distress thermometer(DT), 237 subjects of lung cancer who had been treated before radiotherapy were selected by the cross-sectional survey admitted to Zhejiang Cancer Hospital from May, 2015 to February, 2016. Data were entered into Excel after investigation, and using SPSS 19.0 for statistical analysis, P<0.05 indicating statistically significant differences. Results Lung cancer patients of psychological distress(DT<4) accounted for 89.9%(213/237). The significant frequency of psychological distress(DT ≥ 4) was 10.1%(24/237). The main PL cause of lung cancer psychological distress ranking in the top 10 were economic problems, fear, child care, constipation, housing, dizziness, sleep problems, dealing with children/the old man, breathing, and pain. The psychological distress factors accounted for emotional problems 28.7%(68/237), physical problems 38.4%(91/237), practical problems 28.7%(68/237), communication problems 10.5%(25/237), and religious beliefs 0.8%(2/237). The Spearman correlation analysis showed that gender and psychological distress was not statistically significant(r=0.103,P=0.113). Age and therapy method were positively related with psychological distress(r=0.718,P<0.001; r=0.891,P<0.001)and education level was negatively correlated with psychological distress(r=-0.399,P<0.001). Conclusion The psychological distress for lung cancer radiotherapy patients is given priority to with mild. The age, education level and treatment are the independent factors of affecting psychological DT. The key factors of causing psychological distress are economic problems, fear, child care, constipation, housing, which may provide the right way to relieve the patients' psychological distress.