The juice of three varieties of lychees,Huai Zhi、Yu Hebao、He Li,were chosen as material to study the mechanism of Maillard Reaction of lychee juice during storage.The result showed that the content of sucrose in all varieties of lychee juice decreased gradually during the storage,while the content of fructose and glucose increased at the beginning and then decreased.In the late storage stage,glucose turned brown more quickly than fructose which lead Maillard Reaction more liable;the components of amino acid in different varieties of lychee juice were the same,but with different contents of amino acid,the content of Alanine was the highest,the content of Glutamate,Serine,Histidine,Arginine,Phenylalanine,Lysineall decreased dramatically-up to 80%.This indicated that they were the main amino acids in the Maillard Reaction.The content of Threonine,Proline,Leucine were reduced less.The content of 5-hydroxymethyl furfural(5-HMF)in different varieties of lychee juice increased first and then decreased during the storage.The color difference increased continuously.At the initial period of storage(0～90d),there was a good correlation between the content of 5-HMF and the color difference.