Abstract: Hydrothermal rock is consisted of minerals formed by crystallization in hydrothermal solution.As magmatic rock, sedmertary rock and metamorphic rock, hydrothermal rock is a kind of independent rock.Hydrothermal rock is different from sedimentary rock formed by chemical action, e.g., in sloution temperature and genetic environment.Hydrothermal rock is formed in hydrothermal solution and space within rocks (e.g.fissure), while sedimentary rock is formed in normal temperature and deposit basin.The difference between hydrothermal rock and magmatic rock is that magmatic rock is the product of magma through cooling and coagulation.Hydrothermal rock is not influenced by metamorphism, that is different from metamorphic rock.Hydrothermal rock is more closely related to metasomatite.The main difference is that all minerals for hydrothermal rock are derived from hydrothermal solution, while metasomatite is formed by the metasomatism of hydrothermal solution with wall rocks.