The invention provides a small grain NaY molecular sieve with high Si/Al ratio as well as a preparation method of the small grain NaY molecular sieve. The preparation method comprises following steps:a solid silicon source is mixed with a polymer, and the obtained mixture is subjected to high-temperature treatment under nitrogen protection to obtain a high-activity silicon source; the silicon source, an aluminum source, alkali liquor and water are mixed and aged to obtain a guidance agent; the high-activity silicon source, the guidance agent and water are mixed and stirred to obtain reactiongel; the reaction gel is crystallized, filtered, washed and dried to obtain the small grain NaY molecular sieve with high Si/Al ratio. The preparation method of the small grain NaY molecular sieve with the high Si/Al ratio can directly prepare a Y type molecular sieve with high Si/Al ratio in a short time. Compared with conventional methods, in the same feed molar ratio, the preparation method cansignificantly shorten the crystallization time, improve the Si/Al ratio of products and, the silicon source utilization and the solid content of the silicon source and aluminum source in the reactiongel is high. Furthermore, the yield of single kettle is doubled or more than the yield of the industrial sodium silicate at present.