Zeolitic imidazolate frameworks (ZIFs) have been the focus of interest in adsorption, catalysis, and membrane applications due to their superior thermal and chemical stability, tunable microporous channels, and tailorable physical/chemical properties. In this study, ZIF-7 membranes were successfully prepared on macroporous a-alumina substrate by in situ solvothermal method, without the necessity of seeding or surface modification step. Addition of sodium formate during the reaction facilitates continuous well-intergrown crystalline ZIF-7 layer. As-synthesized ZIF-7 membrane was characterized by XRD, FE-SEM and gas permeation test. The H2 permeance through 5 μm ZIF-7 membrane was 1.9 x 10(-7) mol/m2 x s x Pa with ideal selectivity of H2/CO2 = 15.2.