Abstract: The synergy of zeolite and matrix and the VGO cracking routes were studied by a fixed-bed reactor in which ReUSY zeolite and phosphoric acid modified alumina kaolin as matrix were loaded in different layered or mixed packing ways. It is observed that contacting the matrix first for heavy oil results in a higher conversion compared with that of contacting zeolite first. However，neither the molecular sieve nor the matrix along can make the heavy oil convert effectively. This indicates the preliminary cracking functions of the matrix, resulting in synergistic effect of zeolite and matrix. With the mixing degree of zeolite and matrix increase, the conversion and the liquid product yield rises significantly, while the yields of dry gas and coke decrease slightly. The synergy effect of mixing zeolite and matrix was also discussed in view of the hydrogen distribution in dry gas and LPG products. The data obtained in this work well fit the classic cracking mechanism, but existing protolytic cracking path which contributes to a rise in dry gas yield.