Abstract: This paper discusses the utilization of emulsified heavy oil as raw materials of catalytic cracking. Oil drop diameters after atomization of raw materials decrease when the heavy oil is emulsified, thus the contacting environment of catalyst and raw material and product distribution are improved. When 3000jug/g emulsifying agents are used and the amount of water mixed reaches about 4%, light oil yield increase by 1. 80 percentage point, and dry gas and coke yields lower 0. 33 and 0. 35 percentage point respectively, while the properties of products basically remain unchanged.