Objective: To investigate the indication, efficacy and feasibility of using lateral thoracic subcutaneous-fascial-muscular flap for immediate mammoplasty after modified radical mastectomy with nipple-areola complex (NAC) preservation. Methods: Forty-three patients with flat or small breasts and pre-stage IIIA breast cancer underwent NAC preserving modified radical mastectomy followed by immediate mammoplasty with lateral thoracic subcutaneous-fascial-muscular flap or combined breast reconstruction with prosthesis. The postoperative cosmetic results and complications were evaluated, and the therapeutic effects were assessed by follow-up exam. Results: Operation was successfully performed in all the 43 patients. The average operative time was 1.7 (1.3-2.2) h, average length of overall hospital stay was 17 (13-24) d and average length of postoperative hospital stay was 13 (10-18) d. Postoperative follow-up was performed for 2-12 months, no nipple necrosis occurred and flap infection occurred in two cases; no local recurrence or distant metastasis occurred. The overall patient satisfaction score was 8.5 and the excellent and good rate for objective assessment of breast appearance was 86% (37/43). Conclusion: Using lateral thoracic subcutaneous-fascial-muscular flap for immediate mammoplasty after NAC preserving modified radical mastectomy has the feature of easy performance, short operative time and technical feasibility. It is especially suitable for patients with flat or small breasts and pre-stage IIIA breast cancer.