The invention relates to a porous intergrowth material and a synthetic method thereof, which mainly solves the problems of singular aperture, rather weak acidity and low activity of the porous material synthesized by the prior art. The invention adopts the technical proposal that the porous intergrowth material is produced through properly controlling the nucleation and process of growth of the molecular sieve in the synthetic process of the porous material, wherein the proportion of intergrowth phases is adjustable, and the synthesized porous intergrowth material adopts the compositions including the following mole relation: nSiO2:Al2O3, where n is between 4 and 400 in the formula, and the method is characterized in that the material has more than two phases and an XRD diffraction patternthereof has the d-space maximum value at the lengths of 13.58+-0.1, 11.21+-0.1, 10.04+-0.1, 9.47+-0.1, 9.09+-0.1, 6.6+-0.1, 4.5+-0.1, 3.98+-0.05, 3.86+-0.05, 3.76+-0.04, 3.64+-0.04, 3.53+-0.04, 3.47+-0.02, 3.38+-0.02, 3.19+-0.05 and 2.88+-0.1 angstroms, thereby solving the problems properly. The porous intergrowth material can be used for preparing ethylene and propylene by catalytic-cracking naphtha in the industrial production.