Lignin is a natural macromolecule phenolic polymer existing in plant cell walls. It becomes a new type of feed additive possibly with its multiple biological functions such as anti-microbial, anti-oxidant, anti-diabetic and anti-inflammatory. This review summarizes the physical and chemical characteristics as well as the biological functions of lignin and concludes the application of lignin in livestock production. The aim of this article is to provide reference for developing lignin as a new addit...