Objective To explore the status of nutritional literacy of breast cancer patients undergoing chemotherapy and explore its correlation with treatment self - regulation and perceived social support. Method 256 patients with breast cancer who received chemotherapy treatment in Nantong Cancer Hospital from November 2021 to April 2023 were selected by convenience sampling method as the survey objects. The general information questionnaire nutrition literacy measurement scale for Chinese adults NLMS-CA Chinese version of the treatment self regulation questionnaire TSRQ-C perceived social support scale PSSS surveys breast cancer patients undergoing chemotherapy. Result The NLMS-CA score of patients with breast cancer undergoing chemotherapy was 151. 38± 16. 74 points. Some dimensions scores and total scores of TSRQ-C and PSSS of other breast cancer chemotherapy patients were positively correlated with the scores and total scores of all dimensions of NLMS-CA and the differences were statistically significant all P<0. 05 . The results of multiple linear regression analysis showed that the differences in NLMS-CA scores between patients with different age place of residence cultural level and disease stage and breast cancer chemotherapy were statistically significant all P < 0. 05 . Conclusion The average nutritional literacy level of patients with breast cancer undergoing chemotherapy is relatively good. Clinical medical workers can formulate targeted intervention management measures to improve patients' self treatment adjustment ability and perceived social support level thereby helping patients improve their nutritional literacy and promote health outcomes.