Aim To investigate whether body mass index (BMI) or obesity is associated with the prevalence of abdominal aortic calcification (AAC). Methods 3 116 participants older than 18 were extracted from the data of the National Health and Nutrition Examination Survey (NHANES) from 2013 to 2014. AAC was defined based on dual-energy X-ray absorptiometry (DXA). Logistic regression was performed to analyze the association between BMI or obesity and AAC. The adjusted odds ratio (OR) among subgroups was illustrated in the forest map. Restricted cubic spline regression was fitted to explore the potential nonlinear relationship. Results BMI was inversely associated with AAC even after adjusted for confounders (OR＝0.9,5%CI was 0.81～0.98, P＝0.013), and the obesity was more likely to prevent AAC than normal BMI (OR＝0.8,5%CI was 0.16～0.94, P＝0.037). The association was still significant in the subgroups of male (OR＝0.2,5%CI was 0.69～0.96), age＞60 (OR＝0.9,5%CI was 0.80～0.99), without hypertension (OR＝0.6,5%CI was 0.62～0.93) and without diabetes (OR＝0.7,5%CI was 0.78～0.97). Restricted cubic spline regression revealed a non-linear relationship between BMI and AAC (P＝0.0023). ConclusionBMI was inversely associated with the prevalence of AAC, which could be a new predictor of AAC in the clinical practice.