AbstractLong-chain fatty acid transport protein 1 (FATP1) is a member of the fatty acid transporter family. It facilitates transmembrane transport of fatty acids and participates in lipid metabolism. Lipids are essential components of the cell and organelle membranes of Trichinella spiralis. The nematode has lost the capacity to synthesise the necessary lipids de novo and has instead evolved to obtain fatty acids and their derivatives from its host. This study aims to ascertain the primary biological characteristics and roles of T. spiralis FATP1 (TsFATP1) in lipid metabolism, larval moulting, and the development of this nematode. The results show that TsFATP1 is highly expressed at enteral T. spiralis stages, mainly localised at the cuticle, the stichosome and the intrauterine embryos of the parasite. The silencing of the TsFATP1 gene by TsFATP1-specific dsRNA significantly decreases the expression levels of TsFATP1 in the worm. It reduces the contents of ATP, triglycerides, total cholesterol, and phospholipids both in vitro and in vivo. RNAi inhibits lipid metabolism, moulting, and the growth of this nematode. The results demonstrate that TsFATP1 plays an essential role in lipid metabolism, moulting, and the development of T. spiralis. It could also be a target candidate for the anti-Trichinella vaccine and drugs.