The accumulation of senescent adipose-derived mesenchymal stem cells (AMSCs) in subcutaneous white adipose tissue (WAT) is the main cause for the deterioration of WAT and the subsequent age-related disorders in obesity. The number of AMSCs staining positively for senescence-associated-β-galactosidase (SA-β-Gal) increased significantly after incubation with postprandial triglyceride-rich lipoproteins (TRL), accompanied by an impaired cell proliferation capacity and increased expression of inflammatory factors. Besides, the expression of anti-aging protein, silent mating-type information regulation 2 homolog 1 (SIRT1), was downregulated significantly, while those of acetylated p53 (Ac-p53), total p53, and p21 proteins were upregulated significantly during postprandial TRL-induced premature senescence of AMSCs. Furthermore, the production of intracellular reactive oxygen species (ROS) in the TRL group increased significantly, while pretreatment with the ROS scavenger N-acetyl-L-cysteine effectively attenuated the premature senescence of AMSCs by decreasing ROS production and upregulating SIRT1 level. Thus, postprandial TRL induced premature senescence of AMSCs through the SIRT1/p53/Ac-p53/p21 axis, partly through increased oxidative stress.