A silicalite 1 zeolite membrane was in situ crystallized from a layer of silica species prepared by a novel method of low temperature chemical vapor deposition (LTCVD) on a porous cordierite substrate. XRD patterns show that the membrane consists of MFI type zeolite crystals. The investigation with SEM indicats that the membrane is about 50 μm thick, and covered with well intergrowth MFI zeolite crystals of about 10 μm in size. The EDX analysis confirms that the membrane is composed of silica in the absence of Al, indicating high silica MFI(Silicalite 1) zeolite grown on the support. The ratio of pure gas permeation is 296 for H 2/ iso butane and 13.7 for n / iso butane at room temperature respectively, confirming that the membrane synthesized on the support of cordierite is high quality without pinhole.