The invention relates to a catalytic cracking catalyst and a preparation method thereof. The catalytic cracking catalyst comprises, on the basis of dry base weight, 25 to 75 wt% of a Y molecular sieve, 10 to 30 wt% of an inorganic oxide binder and 15 to 65 wt% of natural mineral matters, wherein the Y molecular sieve has a cell parameter of 24.35 to 24.55 angstroms; the distribution parameter D ofAl in the molecular sieve is no less than 0.3 and no more than 0.8; the mesopore volume of the molecular sieve is 0.15 to 1.0 ml/g and accounts for 30 to 70% of total pore volume; the amount of strong acids in the molecular sieve accounts for 30 to 60% of total acid amount; and a ratio of the amount of the acid B to the amount of the acid L is 20 to 100. The catalytic cracking catalyst provided by the invention has the advantages of excellent heavy oil conversion capability, higher middle distillate yield and lower coke yield when applied to catalytic cracking of heavy oil.