In order to find a suitable zeolite for improving FCC process, in which octane number and gasoline yield are highly enhanced, many types of zeolite were used in cracking reaction of 1-dodecene. From the product distribution, zeolites were classified into three types in FCC reaction. With the type I zeolites, such as SAPO-11, the product pattern was mono-peak distribution by carbon number with high content of olefins and very small content of aromatics. On the other hand, the type II zeolites such as ZSM-5 produced two-peak distribution with high content of aromatics and iso-paraffin in gasoline range. Beta and FCC equilibrium catalyst were classified as the type III zeolites, which showed the intermediate nature between type I and II. From these results, the three types of the zeolite reactivity for FCC could be shown schematically. Octane number of gasoline fraction was estimated from the product composition and it was found that the octane enhancement was attained by use of the type I or type II zeolites, but the simultaneous increase of gasoline yield was obtained by the type II zeolites. © 2010 Asian Network for Scientific Information.