As a microbial biosynthetic lysine polymer,ε-poly-L-lysine exhibits good antimicrobial and biocompatible activities. It has been an increasing demand for ε-poly-L-lysine in industrial applications such as food and medicine. However,the productivity in ε-poly-L-lysine producing strain is low due to the intracellular regulation. The genetic modifications of the producer and the effective fermentation control have enhanced ε-poly-L-lysine productivity to some extent. The studies on the structures of synthetase and degrading enzyme for ε-poly-L-lysine on molecular level and the construction of gene delivery systems for its producer are expected to further improve the quality and the yield of ε-poly-L-lysine.