The invention discloses a catalyst for preparing alkene from methanol, a preparation method for the catalyst and an application of the catalyst. The preparation method comprises the following steps: (1) subjecting a silicon source, an aluminum source, a structure-directing agent, alkali, an organic template agent and deionized water to mixing and stirring, and then, carrying out two-step crystallization under hydrothermal conditions, so as to prepare template agent containing ZSM-5 molecular sieves; (2) adding acid liquor under water-bath stirring conditions, so as to carry out pickling dealumnization treatment on the template agent containing ZSM-5 molecular sieves obtained in the step (1); and (3) subjecting the ZSM-5 molecular sieves subjected to pickling dealumnization in the step (2)to filtering, drying, roasting, ion exchange, re-filtering, drying and re-roasting, thereby preparing a surface-dealuminized ZSM-5 catalyst with a micro-mesoporous structure. The ZSM-5 catalyst prepared by the method has the advantages of high propene selectivity and long catalyst life.