Objective To observe the curative effect of breast benign solid tumor resection with extramammary small incision and its influence on postoperative breast cosmetic effect. Methods A total of 56 patients with benign breast solid tumors admitted to our hospital from June 2021 to June 2022 were selected as the research objects. They were divided into control group and observation group by random number table method, with 28 cases in each group. The control group was treated with traditional large incision, and the observation group was treated with extramammary small incision. The clinical operation indexes, complications and breast cosmetic satisfaction scores were compared between the two groups. Results The operation time, surgical incision, intraoperative blood loss and incision healing time of the observation group were better than those of the control group (P<0.05). The total incidence of complications in the observation group was 7.14%, which was lower than 17.86% in the control group (P<0.05). The scores of breast shape, symmetry and scar satisfaction in the observation group were higher than those in the control group (P<0.05). Conclusion Breast benign solid tumor resection with extramammary small incision can reduce the degree of trauma, shorten the operation time, reduce the amount of bleeding during the operation, promote the healing of the incision, and the cosmetic effect and patient satisfaction are high. Meanwhile, it is a safe and effective treatment plan and is worthy of clinical application.