Abstract: Amino acids in fresh ginseng easily reacted with reducing sugar during the process of red ginseng. The initial maillard reaction products of glutamic acid/leucine/aspartic acid/L-arginine and maltose in red ginseng processed at different temperatures (100 ℃, 110 ℃, 120 ℃) were studied by ESI-MS. The results show that the higher the steaming temperature, the relative content of the products lower. The possible reason is that as the temperature increases, the unstable primary products are decomposed to color materials.