OBJECTIVE: To investigate the body roundness index (BRI) trajectory categories 12 months post-bariatric surgery and to explore the association between BRI and metabolic abnormalities. DESIGN AND METHODS: Subject data were pooled from a tertiary hospital at baseline, 3 and 12 months post-surgery. Anthropometric measurements included the BRI and body mass index (BMI). Metabolic biomarkers comprised triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), glucose (GLU), and uric acid (UA). The BRI level was categorized using growth mixture model, and a multilevel logistic regression model was employed to explore the relationship between BRI and metabolic risk. RESULTS: A total of 669 patients were included in this study, comprising 286 males (42.8%) and 383 females (57.2%), with an average age of 31.70 ± 9.53 years (range of 18 to 65 years). Patients were classified into three BRI trajectory categories. Compared to the Low-gradual decline group, the High-rapid decline group had an increased risk of abnormal HDL-C (OR = 2.84 [95% CI, 1.73 ~ 4.67]), and had the highest proportion of sleeve gastrectomy plus jejunojejunal bypass (SG + JJB) and single anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S) (P < 0.001); while the High-gradual decline group had increased risk of abnormal TG (OR = 3.28 [95%CI,1.67-6.42]), HDL-C (OR = 4.30 [95%CI, 2.31 ~ 8.00]), LDL-C (OR = 2.10 [95%CI, 1.12 ~ 3.93]), and UA (OR = 2.33 [95%CI, 1.33 ~ 4.10]). After adjusting for demographics, lifestyle factors, and surgical procedures, the distribution of risk outcomes remained primarily consistent. CONCLUSIONS: Sleeve gastrectomy (SG) plus procedures could potentially be associated with improvements in abdominal obesity and metabolic status in patients with high BRI. The post-bariatric trajectories based on BRI may offer insights into the metabolic risk levels of Chinese bariatric patients, but further research is needed to confirm these findings.