Objective To investigate the status and influencing factors of health-related hardiness in lung cancer patients undergoing chemotherapy. Methods A total of 286 lung cancer patients undergoing chemotherapy admitted in a grade Ⅲ，class A hospital in Guangzhou from July 2020 to August 2021 were selected using convenience sampling method. The general information questionnaire，Health-related Hardiness Scale，General Self-Efficacy Scale，Social Support Rating Scale were employed for assessment. Results The health-related hardiness scores of lung cancer patients undergoing chemotherapy were（114.51±18.23） points. The results of multiple linear regression analysis showed that gender，family per capita monthly income，pathological stage，self-efficacy，and total social support scores were the main influencing factors of health-related hardiness scores，which explained 43.8% of the total variance. Conclusion The health-related hardiness of lung cancer patients undergoing chemotherapy is at a moderately low level. Medical staff should pay more attention to male patients，patients with lower family per capita monthly income and worse pathological stages. Meanwhile，they need to enhance patients’ self-efficacy and mobilize patients’ social support system，so as to improve patients’ health-related hardiness and promote the physical and mental recovery of the patients.