Abstract: Decomposition kinetics of fructose catalyzed by organic acids in high temperature liquid water was studied at temperatures from 453.15K to 493.15K and pressure of 10 MPa.From the results,it could be seen that the reaction was sped up with organic acids added.Under the same concentration of organic acids, formic acid demonstrated stronger ability to accelerate fructose decomposition than acetic acid.The effects of temperature, organic acids and residence time on the yields of 5-hydromethylfurfural (5-HMF) and levulinic acid(LA) were investigated.Fructose decomposition consisted of two successive reactions, first from fructose to 5-HMF, then from 5-HMF to levulinic acid.From the products profile, it could be concluded that acetic acid sped up the fist step, but had little influence on the second step while both steps were sped up by formic acid.