Abstract: Using β，Y molecular sieve and amorphous silica alumina (ASA) as raw materials for composite support preparation, hydrocracking catalysts with composite supports prepared by different methods were made to see the effect of support on physicochemical properties. It is discovered that the surface area, pore volume and average pore size of the catalyst with composite support made in-situ are lower than that of the catalyst with mechanical mixed molecular sieve and ASA composite support. The conversion rate, naphtha selectivity and chemical raw material yield are lower than the latter at the conditions of 360 ℃，8.0 MPa，LHSV of 2.0 h-1 and H2/oil of 1000 using hydrotreated Daqing VGO as feed , but higher liquid yield than the latter.