Objective To investigate the relationship between healthy eating behavior and nutritional literacy and eating attitude in breast cancer patients undergoing chemotherapy. Method Conduct retrospective study selecting 128 breast cancer patients who received chemotherapy at the Fuyang Cancer Hospital from January 2022 to June 2023 as the study subjects. Collect demographic data clinical data and use the Chinese Cancer Patients Nutrition Knowledge-Attitude-Behavior Survey Questionnaire and the Chinese Adult Nutrition Literacy Measurement Scale NLMS-CA to investigate patients' dietary behaviors attitudes and nutrition literacy. Result The average score of healthy eating behavior of 128 patients with breast cancer chemotherapy was 55. 94± 13. 13 . The results of univariate analysis showed that Demographic and disease characteristics such as age BMI working status residence status education level per capita monthly family income menopausal status caretakers whether to relapse were significantly correlated with the score of healthy eating behavior of patients P<0. 05 . The results of Pearson correlation analysis showed that the healthy eating behavior score of patients was significantly positively correlated with the total score of NLMS-CA scale scores of all dimensions and total score of eating attitude P< 0. 05 . Multiple linear regression analysis showed that eating behavior score was significantly correlated with the total score of NLMS-CA scale and the total score of eating attitude P< 0. 05 . Conclusion The healthy eating behavior of breast cancer patients with chemotherapy is affected by many factors and it is closely related to its nutrient and eating attitude which should be paid attention to during intervention.