Method for preparing high silica alumina ratio NaY molecular sieve

A preparation method of the NaY molecular sieve with high silica-alumina ratio includes: preparing the high alkalinity silica-alumina gel (3.0-6.0)Na2O:Al2O3:(7-20)SiO2:(100-600)H2O and the low alkalinity silica-alumina gel (0.5-3.0)Na2O:Al2O3:(7-20)SiO2:(100-600)H2O obtained by evenly mixing conventional directing agent, silicon source, aluminum source and water, heating up the high alkalinity silica-alumina gel to 90-110 DEG C, crystallizing for 0.5-20 hours, adding the low alkalinity silica-alumina gel, filtering, washing, drying and obtaining the NaY molecular sieve. The modified NaY molecular sieve is applicable to the catalyst preparation of catalytic cracking, hydrogen cracking and isomerization.