NOVELTY - A porous symbiotic material comprises silicon dioxide (SiO 2) and aluminum trioxide (Al 2O 3). The material has more than two kinds of phases, and its X-ray diffraction pattern ( Angstrom ) has maximum difference between d and space, at 13.58 plus minus 0.1, 11.21 plus minus 0.1, 10.01 plus minus 0.1, 9.47 plus minus 0.1, 9.09 plus minus 0.1, 6.6 plus minus 0.1, 4.5 plus minus 0.1, 3.98 plus minus 0.05, 3.86 plus minus 0.05, 3.76 plus minus 0.04, 3.64 plus minus 0.04, 3.53 plus minus 0.04, 3.47 plus minus 0.02, 3.38 plus minus 0.02, 3.19 plus minus 0.05 and 2.88 plus minus 0.1.    USE - Porous symbiotic material for industrial production of ethylene and propylene by naphtha catalysis and crack.    ADVANTAGE - The material overcomes single aperture of porous material, weak acidity and low activity. Its synthesis has well controlled nucleation and growing process of molecular sieve; and its symbiotic phase proportion is adjustable.    DETAILED DESCRIPTION - Porous symbiotic material comprises silicon dioxide (SiO 2) and aluminum trioxide (Al 2O 3), with molar ratio of nSiO 2:Al 2O 3. The material has more than two kinds of phases, and its X-ray diffraction pattern ( Angstrom ) has maximum difference between d and space, at 13.58 plus minus 0.1, 11.21 plus minus 0.1, 10.01 plus minus 0.1, 9.47 plus minus 0.1, 9.09 plus minus 0.1, 6.6 plus minus 0.1, 4.5 plus minus 0.1, 3.98 plus minus 0.05, 3.86 plus minus 0.05, 3.76 plus minus 0.04, 3.64 plus minus 0.04, 3.53 plus minus 0.04, 3.47 plus minus 0.02, 3.38 plus minus 0.02, 3.19 plus minus 0.05 and 2.88 plus minus 0.1.    n=4-400, preferably 8-200.    An INDEPENDENT CLAIM is included for a synthesis of porous symbiotic material comprising:    (A) mixing silicon source, aluminum source, alkali source, template M and water, with molar ratio of SiO 2/Al 2O 3 of 8-200, hydroxyl group/SiO 2 of 0.001-10, M/SiO 2 of 0-3, and water (H 2O)/SiO 2 of 10-500, and regulating pH at 8-14 by dilute acid solution;    (B) putting mixed reaction mixture into the closed high-pressure kettle for crystallization for 8-200 hours at 80-220 degrees C;and    (C) taking crystals, washing, filtering and drying.    The silicon source is organic silicon, unset silicon dioxide, silica sol, solid silicon oxide, silica gel, diatomite or water glass; aluminum source is aluminate, meta aluminate, aluminum salt, hydroxide of aluminum, oxide of aluminum or ore containing aluminum; alkali source is hydroxide of alkali metal; and template M is organic ammonium or inorganic ammonium.