Objective: We attempt to explore the effect of accurate angle of healthy side upper limb on body posture in radical mastectomy. Methods: We enrolled 150 patients who received radical mastectomy in our hospital and averagely randomized them into three groups: control group A, control group B and observation group. In control group A, the intraoperative abduction angle of healthy side upper limb was 90°, in control group B it was 0°, and observation group 75-80°. We scored the comfort level of the healthy side upper limb of patients in three groups prior to anesthesia induction and 24 hours after operation. At the end of operation, we scored the first assistant surgeon’s, anesthetist’s and circulating nurse’s satisfaction with standing space, the convenience of intravenous administration and convenience of observing transfusion during operation respectively. Results: There was significant difference in the comfort level between observation group and control group A, B (P 0.05). Anesthetist’s satisfaction with the convenience of intravenous administration during operation was 100% in observation group and control group A while it was 36% in control group B. There was a significant difference (P<0.05). Circulating nurse’s satisfaction with the convenience of observing transfusion during operation was 100% in observation group and control group A while it was 30% in control group B. There was a significant difference (P<0.05). Conclusions: When the accurate angle of healthy side upper limb in the body posture in radical mastectomy is 75-80°, it does not affect the standing space of the first assistant surgeon, intraoperative administration by anesthetist and observation of transfusion by circulating nurse, and avoids intraoperative position-related complications of patients.