Abstract: By analyzing the distribution characteristics of hydrothermal altered minerals in Longtoushan gold deposit，it is considered that gold mineralization is closely related to tourmalinization and silicification.According to the K-Ar isotopic dating and so on，tourmalinization and silicification belong to the earliest hydrothermal alteration，which are related to hyolitic porphyry and breccia lava.Sericitization and kaoliniztion relate to the intrusions of granite-porphyry and biotite granite-porphyry at the later stage.The study results show that the depth of gold mineralization in this area is slightly greater than others which were often mentioned.

Key words: Longtoushan, Gold mineralization, Hydrothermal alteration, Tourmalinization