Objective To explore the changing characteristics of nutritional status and its correlation with Cancer-related Fatigue (CRF) among elderly Non-small Cell Lung Cancer (NSCLC) patients undergoing chemotherapy, so as to provide reference for developing targeted intervention to alleviate CRF. Methods Totally 115 elderly NSCLC patients undergoing chemotherapy were selected, who were then investigated using Nutritional Risk Screening 2002 (NRS-2002) at one day before (T0) and the 7th day of the first cycle of chemotherapy （T1）, one day before (T2) and the 7th day of the second cycle of chemotherapy （T3）, and the 7th day after the fourth cycle of chemotherapy（T4）, and the patients were also investigated utilizing CRF scale at T4. Results The score of NRS-2002 was (3.05±1.19), (3.80±1.24), (2.85±1.22), (3.19±1.21) and (3.06±1.09) at T0, T1, T2, T3 and T4 respectively, and there was significant difference among the scores (P<0.01).The incidence of malnutrition was 10.4%, 27.8%, 8.7%, 18.3% and 14.8% at each time point. The total CRF score and the score of physical fatigue, emotional fatigue, cognitive fatigue was (40.60±6.48), (14.58±3.87), (14.28±1.17) and (11.74±2.84) at T4. The NRS-2002 score at each time point were positively and significantly correlated with the score of physical fatigue, cognitive fatigue and the total CFS score at T4 (P<0.01 for all). Conclusion The proportion of malnutrition and nutritional risk among elderly NSCLC patients during chemotherapy are high, and its trend of change appears as a "wave". In addition, nutritional status has something to do with CRF, so it is necessary to conduct active nutritional support to reduce the degree of CRF.