Abstract: The MFI (ZSM-5 and silicate-1) membranes with porous α-Al₂O₃ substrates were synthesized by secondary growth method. The results of scanning electron microscopy (SEM) and X-ray diffraction (XRD) indicate that the membranes with 5 μm thickness are composed of well-intergrown MFI crystals, which completely covers on the α-Al₂O₃ substrates in random orientation. The gas permeation measurements reveal that the resulting membranes are of high quality with few non-zeolitic pores. In addition, the separation properties of H₂S/CH₄ through the synthesized MFI membranes were investigated. Under the osmotic pressure of 0.3 and 0.5 MPa, the separation factors of H₂S/CH₄ by silicate-1 zeolite membrane are 1.99 and 4.44, and the separation factors of CH₄/H₂S by ZSM-5 zeolite membrane are 6.71 and 12.85, respectively.