Abstract:L-ornithine is a non-protein amino acid involved in urea metabolism and polyamines biosynthesis. Due to the positive functions in treating liver diseases and enhancing immunity, L-ornithine is widely used in medicine and food industry. Currently, L-ornithine production mainly depends on chemosynthesis, enzymatic catalysis and microbial fermentation. Among them, microbial fermentation has gradually become the focus for L-ornithine production owing to its superiority in cost and environmental protection. In this article, recent progress in the development of high L-ornithine producing strains through genetic engineering is summarized, the metabolic engineering strategies for improving L-ornithine production in Corynebacterium glutamicum are discussed, and the future direction is predicted.