Catalytic cracking catalyst for cracking coker gas oil and preparation method thereof

The invention provides a catalytic cracking catalyst for cracking coker gas oil and a preparation method thereof. The catalyst is prepared from 15-70 wt% of a molecular sieve, 15-60 wt% of clay, 8-30wt% of pseudo-boehmite and 3-20 wt% of a binder. The preparation method comprises the following steps that the rare-earth, phosphorus and magnesium compound modified Y-type molecular sieve is prepared, wherein the step is characterized in that phosphorus modification of the molecular sieve is carried out before magnesium modification; and then the rare-earth, phosphorus and magnesium compound modified Y-type molecular sieve, the clay, the pseudo-boehmite and the binder are mixed and pulped, and then spray drying, washing, filtering and drying are sequentially carried out so as to prepare the catalyst. The catalyst provided by the invention has the advantages that the adsorption capacity of nitride and aromatic hydrocarbon in the coker gas oil and an acid center of the catalyst can be reduced, the negative influence of the coker gas oil on the catalytic cracking reaction is reduced, and the catalyst has excellent coke selectivity under the circumstances that the conversion rate is increased and heavy oil is reduced.