Abstract:To research the effect of litchi polyphenol （LP）on weight loss and immunity enhancement by nutritionally obesity models.72 C57BL/6 mice were randomly divided into two groups.12 mice in the normal control group were fed basic feed and 60 mice in the high-fat group were fed high-fat feed.After feeding high fat diet for 4 weeks，60 mice were randomly divided into model group，L-carnitine group（500 mg/kg），low dosage group of LP（300 mg/kg），medium dosage group（400 mg/kg），high dosage group（500 mg/kg），and 12 mice in each group.Animals continued to be fed high-fat diets，while mice in each group were given the above drugs for 2 weeks by gavage.After the experiment，weight，fat weight，Lee's index，spleen index and thymus index and（immunoglobulin A）IgA，immunoglobulin G（IgG）and immunoglobulin M（IgM）contents of mice in each group were compared.Compared with model group，the mice weight，Lee's index，fat weight of mesentery，double kidney week，epididymis of dosage group of LP were reduced significantly （p＜0.05），fat weight of double kidney week，epididymis of middle and low dose group were lower than that in the model group （p＜0.05）.The content of IgA in the serum of high dosage group of LP was significantly higher than that of the model group（p＜0.05）.Compared with the model group，middle dose group and low dose group had higher difference in IgM and IgG.The research results shoed that LP could inhibit the diet amount and reduce the weight of obese rats induced by high-fat feed and has obvious effect of losing weight and improving immunity.