Method for synthesizing fine grain MCM-22 molecular sieve

Disclosed is a method for synthesizing fine grain MCM22 molecular sieve, wherein the templating agent employs the product yield of hexanolactam hydrogenation, and mainly comprises hexamethyleneimine, water, a small amount of byproduct and hexanolactam (reacted unconcompletely), the method comprises using silicon source, aluminium source, alkali source, templating agent and deionized water as reaction raw material, crystallizing for a finite period of time at 135-185 deg. C, untill completion of the reaction, obtaiting the needed molecular screen through hydrothermal synthesis, the invention is characterized in that organic additives can be charged into the reaction raw material, the organic additive can be sodium dodecylbenzene sulfonate, polyethylene glycol type surface active agent, or their mixture, the molecule ratio of the charged additive and the silicon dioxide in the reaction raw material is 0.01-2.5.