The Wnt/beta-catenin signaling pathway alters adipocyte differentiation by inhibiting adipogenic gene expression. beta-catenin plays a central role in the Wnt/beta-catenin signaling pathway. In this study, we revealed that tumour necrosis factor-alpha (TNF-alpha), a potential negative regulator of adipocyte differentiation, inhibits porcine adipogenesis through activation of the Wnt/beta-catenin signaling pathway. Under the optimal concentration of TNF-alpha, the intracellular beta-catenin protein was stabilized. Thus, the intracellular lipid accumulation of porcine preadipocyte was suppressed and the expression of important adipocyte marker genes, including peroxisome proliferator-activated receptor-gamma (PPARgamma) and CCAAT/enhancer binding protein-alpha (C/EBPalpha), were inhibited. However, a loss of beta-catenin in porcine preadipocytes enhanced the adipogenic differentiation and attenuated TNF-alpha induced anti-adipogenesis. Taken together, this study indicated that TNF-alpha inhibits adipogenesis through stabilization of beta-catenin protein in porcine preadipocytes.