In the current research, the polymorphism of FATP4 gene was analyzed in Erlang Mountainous chickens. A total of nine genetic variants were identified by FATP4 gene sequencing analysis across the chicken samples. Significant associations (p < 0.05) were observed for two SNPs (g.5608778C>T and g.5608814G>A in exon 6) with certain carcass traits (such as live weight, carcass weight, eviscerated weight) in S01 and S05 populations, respectively. Meanwhile, in S05 population, haplotype 3 (T-G) and haplotype 2 (C-A) were associated with higher and lower partial carcass traits such as live weight, carcass weight, eviscerated weight and semi-eviscerated weight, respectively. Moreover, we investigated the expression profile of this gene during ontogenesis in Mountainous black-boned chicken. Quantitative real-time PCR analysis showed that FATP4 mRNA had the highest expression level in small intestine tissue over all other tissues examined. The FATP4 mRNA levels presented remarkable developmental changes with age in the various tissues. These results suggested that the FATP4 gene might play an important role in controlling chicken carcass traits.