The invention provides a synthesis method of a NaY molecular sieve. The synthesis method includes following steps: (1), mixing silicone-containing substance, acidic aluminum salt, sodium aluminate and/or sodium metaaluminate with guiding agent to form gel; (2), performing ultrasonic dispersion on the gel; (3), subjecting the gel after going through ultrasonic dispersion to crystallizing, filtering, washing and drying sequentially. By using the synthesis method, crystallizing speed can be increased, and the NaY molecular sieve high in crystallinity and high silicone-aluminum ratio can be prepared.