The invention relates to a method for preparing 4-hexene-3-ketone by carrying out dehydration on 4-hydroxy-3-hexanone, mainly aiming at solving the problems of low catalyst activity, high reaction temperature and slow space velocity in the prior art. The catalyst used by the method is prepared by the following steps of: mixing a silicon source, an aluminium source, template agent R1, template agent R2 and water, and adjusting the pH of the reaction mixture to be 8-14 with inorganic base; in the reaction mixture, controlling the molar ratio between Al2O3 and SiO2 to be 0.003-0.05, controlling the molar ratio of R1 to SiO2 to be 0.1-2, controlling the molar ratio of H2O to SiO2 to be 10-100 and controlling the molar ratio of R2 to SiO2 to be 0.05-2; and carrying out hydrothermal crystallization on the mixture for 1-10 days at the temperature of 100-250 DEG C to obtain the catalyst, wherein R1 comprises at least one selected from tetramethyl ammonium hydroxide, tetraethyl ammonium hydroxide, tetrapropyl ammonium hydroxide or tetrabutyl ammonium hydroxide, and R2 comprises at least one selected from beta-diketone, beta-diketone salt, oxalic acid, oxalate, catechol or 8-hydroxyquinoline. The technical scheme better solves the problems, and can be used in the industrial production of the 4-hexene-3-ketone prepared by the 4-hydroxy-3-hexanone.