Objective The aim of this study was to explore the effect of androgen deficiency on serum hormone levels, visceral fat accumulation and inflammatory gene expression in miniature pigs fed a high-fat diet (HFD). Methods Sexually mature male Chinese Wuzhishan miniature pigs were divided into three groups (animals/group) as follows:intact male pigs (SHAM), castrated male pigs (CAS) and castrated male pigs plus testosterone treatment (CAS+T). The pigs were fed a HFD diet for 12 weeks. Serum levels of testosterone and leptin were measured and visceral fat were dissected and weighted. qRT-PCR was performed to determine the mRNA expression levels of lipogenic, lipolysis and inflammation related genes. Results (1) Serum testosterone levels were significantly decreased but serum leptin levels were significantly increased in the castrated pigs. These effects were recovered after testosterone treatment. (2) Visceral fat percentage was significantly increased in the castrated pigs, and testosterone treatment reduced the increased visceral fat in the castrated pigs. (3) Castration and testosterone treatment had no significant effects on the expression levels of lipogenic genes (FAS and ACC) and lipolysis genes (HSL and ATGL) in pigs fed a HFD. (5) Castration significantly induced the expressions of inflammatory genes including Leptin, CD68, CCL16, CCL23 and SAA, and testosterone treatment recovered the expressions of the above genes in the castrated pigs. Conclusions Castration-induced testosterone deficiency promotes visceral fat accumulation and upregulates the expression levels of inflammatory genes in miniature pigs fed a HFD. Moreover, testosterone treatment ameliorates castration-induced visceral fat accumulation and inflammatory response in HFD-fed pigs.