Objective To determine the dynamic change of chemotherapy-related symptoms during different chemotherapy circles among lung cancer patients, and to analyze the relationship with functional status. Methods A basic information questionnaire, the Therapy-related Symptom Checklist （TRSC）, and the Karnofsky performance score were utilized in a longitudinal survey among lung cancer patients after their first （T1）, third （T2） and fifth chemotherapy circle （T3）.Generalized estimating equation was performed to explore the differences of the TRSC score and Karnofsky score, Kruskal-Wallis test was used to compare the scores of 25 symptoms in TRSC, and Pearson correlation was utilized to analyze the relationship between TRSC and the Karnofsky scores at each time point. Results A total of 246, 221 and 209 lung cancer patients completed the survey at the three time points.The total TRSC score was （17.61±9.62）,（19.47±7.99） and （22.93±9.02）, and the Karnofsky score was （79.13±14.22）,（76.98±13.85） and （72.85±13.45） respectively.The TRSC score at T3 was significantly higher than those at T1 and T2, and the Karnofsky score at T3 was significantly lower than that at T1 （P＜0.05 for all）.Among the 25 symptoms in TRSC, the severity of 14 symptoms were significantly different at the three time points. There were significant negative correlation between the total score of TRSC and the Karnofsky performance at T1, T2, T3 （P＜0.05 for all）. Conclusion Lung cancer patients experience severe chemotherapy-related symptom distress during each treatment circle, and their symptoms and functional status deteriorate gradually along with the treatment time.At each treatment stage, the more severe symptom burden they experience, the greater the functional impairment.