Objective To investigate the effect of hypofractionated intensity-modulated radiotherapy on tumour marker levels and breast aesthetics in patients undergoing breast-conserving therapy for early breast cancer. Methods A total of 80 patients who underwent breast-conserving therapy for early breast cancer in Tangshan People's Hospital from January 2022 to October 2023 were selected as the research subjects, and they were randomly divided into control group (58 patients) and observation group (22 patients). The control group was given conventional fractionation radiotherapy, and the observation group was given hypofractionated intensity-modulated radiotherapy. The tumour marker levels, breast aesthetics, prognosis and adverse reactions were compared between the two groups. Results After treatment, the levels of CA125, AFP and CEA in the observation group were lower than those in the control group (P <0.05). The excellent rate of breast aesthetics in the observation group was 95.45%, which was higher than 87.93% in the control group, but the difference was not statistically significant (P >0.05). There was no significant difference in local control rate, distant metastasis rate, 1-year survival rate and follow-up time between the two groups (P >0.05). The incidence of adverse reactions in the observation group was 9.09%, which was lower than 15.52% in the control group, and the difference was not statistically significant (P >0.05). Conclusion The effect of hypofractionated intensity-modulated radiotherapy and conventional fractionation radiotherapy in patients undergoing breast-conserving therapy for early breast cancer is good. Both can improve breast aesthetics and improve prognosis, and have good safety. However, hypofractionated intensity-modulated radiotherapy can further control the level of cancer markers in patients, which is worthy of clinical application.