Abstract: Characteristic color development and free radical scavenging activity in Xyl-Gly Maillard reaction system was investigated under two phases of high and low temperatures.The Xyl-Gly Maillard reaction system was heated at 60℃ for 0, 0.5, 1h and then set at 4℃ for 15d.The results showed that, the longer time heated at 60℃, the greater initial values of absorbance, b and free radical scavenging rates.The absorbance intensity gradually increased, and the color values of L, a, b all decreased during 15d at 4℃. The characteristic peaks at 265, 580 and 630nm appeared on the UV-Vis, with increased absorbance intensity at 580 and 630nm and disappearance of the peaks at 265nm. ABTS and DPPH radical scavenging rates increased with increasing time at 4℃. Preheating could promote the Maillard reaction in low temperature, but the characteristic peak at 265nm disappeared as heating temperature increased.