Objective To explore the effect of periumbilical incision negative pressure liposuction in the contouring of lateral edge line of abdominal rectus abdominis muscle. Methods A total of 40 patients with abdominal obesity who received abdominal contouring in the Outpatient Department of Changsha Fanhou Ye Zhenmei Medical Beauty Co., Ltd. from July 2024 to March 2025 were selected as the research subjects, and they were divided into the control group and the study group by the random number table method, with 20 patients in each group. The control group underwent conventional liposuction surgery, and the study group received periumbilical incision negative pressure liposuction for contouring on the basis of the control group. The definition score of the lateral edge line of abdominal rectus abdominis muscle, abdominal three-dimensional volume, subcutaneous fat thickness and satisfaction were compared between the two groups. Results The definition scores of the lateral edge line of abdominal rectus abdominis muscle in the study group at 1 and 3 months after operation were higher than those in the control group (P <0.05). The abdominal threedimensional volume and subcutaneous fat thickness in the study group at 1 and 3 months after operation were lower than those in the control group (P<0.05). The satisfaction rates in the study group at 1 and 3 months after operation were higher than those in the control group (P<0.05). Conclusion The application of periumbilical incision negative pressure liposuction in the contouring of the lateral edge line of abdominal rectus abdominis muscle has a definite effect. It can effectively improve the clarity of the lateral edge line of abdominal rectus abdominis muscle while optimizing the overall abdominal contour, reduce the thickness of subcutaneous fat, reduce the abdominal volume, and help to improve the subjective satisfaction of patients, which is worthy of clinical application.