Methane hydrate is the ice-stated solid crystals composed by water molecules and molecules of methane gases. Water molecules make a cage where space holds inside, molecules of methane gases are encircled in this space. Commonly, a chemical compound that gas molecules are taken into a cage made by water molecules is called as gas hydrate, gas molecules belong to methane are called as methane hydrate. In this paper, structure and chemical properties of methane hydrate, the synthesized experiments and a stable region of methane hydrate were mentioned. Methane hydrate in seabed deposit has still been attracted an attention as a recent methane resource, a marine earthquake-detecting method was introduced by using the submarine pseudo-reflection as a surveying method of methane hydrate in seabed. 10 refs., 7 figs., 1 tab.