Abstract: Objective To evaluate the incidence and risk factors of symptomatic radiation pneumonitis（RP） in patients with driver gene positive locally advanced non-small cell lung cancer（NSCLC）. Methods From January 2017 to April 2020, patients with inoperable stageⅢ NSCLC who received targeted therapy followed by sequential thoracic radiotherapy in Guangdong Provincial People's Hospital were retrospectively analyzed. Radiation pneumonitis was graded according to the common terminology criteria for adverse events 5.0. The symptomatic RP was defined as ≥ grade 2. Chi square test and nonparametric Kruskal Wallis test were used to evaluate the potential clinical and dosimetric risk factors. Results Among the 13 patients, 6 （46.1%） had symptomatic RP. There were 5 cases of ≥ grade 2 RP and 1 case of grade 3 RP. After steroid treatment, all RP were recovered and resulted in pulmonary fibrosis grade 1~2. Univariate analysis showed that age, history of chronic obstructive pneumonia and other clinical factors were not associated with ≥ grade 2 RP. Dose factors such as V20 and average lung dose were not related to ≥ grade 2 RP. Conclusion The incidence of ≥ grade 2 RP after targeted therapy followed by sequential radiotherapy is high. No clinical or dosimetric risk factors related to symptomatic RP were found.