Objective：To evaluate the safety and feasibility of transversus thoracic muscle plane-pectoral nerves（TTP-PECS）block in modified radical mastectomy for breast cancer under opioid-sparing general anesthesia. Methods：Sixty patients scheduled for modified radical mastectomy for breast cancer were randomly divided into two groups：the TTP-PECS block combined with opioid-sparing general anesthesia group（TO group）and the conventional general anesthesia group（GA group），with 30 patients in each group. The systolic blood pressure（SBP），diastolic blood pressure（DBP），and heart rate（HR）of the two groups were observed and recorded at various time points；the pain visual analogue scale（VAS）scores at rest and on movement were recorded at anesthesia induction（T₀）， just before intubation（T₁），at skin incision（T₂），at breast specimen removal（T₃），and at the end of surgery（T₄）；and the quality of recovery-40（QoR-40）scores were assessed 24 h postoperatively. The incidence of adverse events during the perioperative period was also recorded. Results：Compared with T0，the SBP，DBP，and HR of both groups were significantly decreased at T₁-T₄（P < 0.05），but there was no statistically significant difference between the two groups at each time point（P > 0.05）. The VAS scores at 2 h，6 h，and 12 h postoperatively，both at rest and on movement，were significantly lower in the TO group than in the GA group（P < 0.05）. The total QoR -40 scores and scores for emotional state，physical comfort，psychological support，and pain were significantly higher in the TO group than in the GA group 24 h postoperatively（P < 0.05）. The incidence of cough reflex during induction and postoperative nausea and vomiting were significantly lower in the TO group than in the GA group（P < 0.05）. Conclusion：TTP-PECS block combined with opioid-sparing general anesthesia is safely used in modified radical mastectomy for breast cancer，providing effective postoperative analgesia，reducing the incidence of postoperative nausea and vomiting，and improving early recovery quality for patients.