In this paper, four different Salen-Al was prepared, The structures of Salen-Al have been investigated using different characterization techniques such as IR, UV, 1H-NMR, EA and ICP, chose one of the four Salen-Al which had the highest catalytic activity, and compounded with quaternary ammonium salt to form the binary catalyst system. Carbonated soybean oil was prepared by the reaction of epoxidized soybean oil and carbon dioxide, and characterized by IR, 1H-NMR. While the reaction pressure, composite ratio were examined. Studies had shown that binary catalytic system in the temperature of 120 ℃, pressure at 2 MPa, Salen-Al and quaternary ammonium salt composite ratio at 1:1 had high catalytic efficiency, reaction time at 8h the conversion was as high as 76.8%, compared with using single catalyst the catalytic efficiency had improved significantly.