Increasing attention is attached to L-carnitine as a new type of feed additive at present. This review had systematically summarized the facilitation of fatty acids β-oxidation of L-carnitine, and some newly discovered functions such as anti-apoptosis, anti-oxidation and immunoregulation. Furthermore, the possible mechanisms of the anti-oxidative and immunoregulative functions of L-carnitine were also discussed, which would provide theoretical basis for further research and application of L-carnitine in animal production.［Chinese Journal of Animal Nutrition，2011，23（3）：357-363］