Preparation method of Y-shaped molecular sieve

The invention provides a preparation method of a Y-shaped molecular sieve. The preparation method comprises the following steps that (1) ion exchange is performed on a NaY molecular sieve and an ammonium salt solution, filtering and washing are carried out, then a filter cake and rare-earth salts are mixed and roasted to obtain a rare-earth modified Y-shaped molecular sieve; (2) ion exchange is performed on the rare-earth modified Y-shaped molecular sieve, a phosphorus-containing compound and an ammonium salt, filtering, washing and roasting are carried out to obtain a rare-earth and phosphorus compound-modified Y-shaped molecular sieve; and (3) ion exchange is performed on the rare-earth and phosphorus compound-modified Y-shaped molecular sieve and a magnesium salt solution, filtering andwashing are carried out, and thus the rare-earth, phosphorus and magnesium compound-modified Y-shaped molecular sieve is obtained. The modified molecular sieve provided by the invention has excellentheavy oil conversion ability and coke selectivity, and the contradiction of weakening of strong acid and heavy oil conversion in pores of the molecular sieve can be solved.