The present invention discloses a synthesis method, a product and applications of mordenite having mesopores and micropores. According to the present invention, the method comprises stepwise preparation of an initial gel and stepwise crystallization; the mordenite obtained by the method has micropores and mesopores, and has excellent performances and stability in the fields of adsorption and catalysis; and the synthesis method is simple, and especially the broad industrial application prospect is provided when the mordenite is applied in the dimethyl ether carbonylation reaction catalyst.