Abstract: Objective: To investigate the relationship between body mass index (BMI) and the area of superior mesenteric artery (SMA) -aorta (AO) by enhanced CT scans. Methods: 538 patients referred for abdominal enhanced CT scans without clinical evidence of suspect SMAS were included. The patients were divided into four groups according to BMI (group 1:BMI <18.5 kg/m<sup<2</sup<; group 2:BMI 18.5~24.9 kg/m<sup<2</sup<; group 3:BMI 25~29.9 kg/m<sup<2</sup<; group 4:BMI ≥ 30 kg/m<sup<2</sup<) in both genders. The relationships between the area and BMI as well as BMI category of different genders were analyzed. Results: For both females and males, there was significant positive correlation between the area and BMI (<i<r</i<=0 0.50, <i<r</i<=0 0.55, respectively, <i<P</i<<0.01). The correlations between the BMI category and the area were moderate positives (<i<r</i<=0 0.43, <i<r</i<=0 0.45, respectively, <i<P</i<<0.01). The results showed a positive correlation between BMI and the area. Conclusion: The area measured by enhanced CT scans significantly correlates with BMI in normal population. The mean values can be used for the screening and diagnosis of superior mesenteric artery syndrome.