In order to study temperature variation characteristics in gas tank during natural gas hydrate formation, applied is a home­made three-dimensional natural gas hydrate simulation equipment to form methane hydrate from methane gas and aqueous solution and investigate the whole formation process of methane hydrate in porous media through temperature-pressure variation. The investigation results show that methane gas is injected from vertical center well into surrounding regions, accordingly, the central region temperature rises and temperature around the central region also rises gradually, and hydrate gathers from the center well outwards. Hydrate in porous media will produce the effect of climbing wall due to capillary action of porous media and more hydrate will form outside and show inhomogeneous distribution in porous media.