Objective To explore the effect of one-stage breast reconstruction on tumor marker levels in patients with early breast cancer (EBC). Methods A total of 70 patients with EBC admitted to the Cancer Hospital of General Hospital of Ningxia Medical University from March 2022 to March 2025 were selected as the research subjects, and they were divided into group A and group B by the random number table method, with 35 patients in each group. Group A received oncoplastic breast-conserving surgery, and group B received one-stage breast reconstruction. The clinical efffcacy, treatment-related indicators, aesthetic effect, levels of tumor markers and complication rate were compared between the two groups. Results The total effective rate of group B (94.29%) was higher than that of group A (74.29%) (P<0.05). The operation time of group B was longer than that of group A, the postoperative drainage tube indwelling time and hospitalization time were shorter than those of group A, and the drainage volume was more than that of group A (P<0.05). There was no statistically signiffcant difference in aesthetic effect between the two groups (P>0.05). The levels of all tumor markers in group B at 2 weeks after treatment were lower than those in group A (P<0.05). The incidence of complications in group B was 2.86%, which was lower than 20.00% in group A (P<0.05). Conclusion For patients with EBC, one-stage breast reconstruction can ensure favorable aesthetic effect, effectively improve clinical efffcacy, shorten postoperative recovery cycle, down-regulate tumor marker levels and reduce the incidence of complications.