Abstract: Acrylic acid and its ester derivatives are principal raw materials in the manufacture of polymeric products. The polymers made of acrylic acid and its derivatives are characterized by color lasting, stability to light, moderate heat as well as weathering. And they are widely applied in surface coatings, textiles, adhesives, paper treatment, polishes, leather, fibers, and super-absorbent polymer, etc. Based on detailed investigation of related literatures, the dehydration of methyl lactate was carried out over molecular sieve catalyst in a fixed-bed reactor at high temperature with CO2 as carrier gas. In the experiments, the type of molecular sieve catalyst, the effect of ion exchanger, reaction temperature and the type of carrier gas were investigated. The results showed that the optimum conditions were obtained over modified NaY catalyst with KCL as ion exchanger, and a combined yield of 36.7% for methyl acrylate and acrylic acid from methyl lactate was gained over this catalyst at 275℃ with CO2 as carrier gas.