Zhongshangou Au deposit, located in northern of Hebei province, is a vein- type mineralization and is obviously controlled by near N—S trending fault structure. It occurs in Shuiquangou alkaline complex. The mineralization alterations mainly include potassification, silicification, argillaceous lithification and epidote formation. The ore is mainly produced in vein, veinule and breccia. Baseed on vaious alteration mineral assemblages and intersecting relations, the mineralization stages can be divided into potassium— low sulfide, milky quartz—sulfide stage, high- silicification and sulfide, and carbonate stage. According to the detailed structural survey and Deposit geochemistry, the potassium— low sulfide stage is controlled by sino- lateral tectonic movement and may be of medium temperature and medium salinity (330~290℃; δ18 OH2O: 5.26~6.76‰; δ18OH2O: 5.26~6.76‰; δD: -96.3~89.9‰). The silicification—sulfide stage is the result of the transition from left- lateral movement to right- lateral extension, and the high- angle large- scale filling occurs. Due to the occurrence of large- scale fluid boiling and thermal miscibility (δ18OH2O: 0.41~6.47‰; δD:-80.2~-92.9‰), the formation of milky quartz—sulfide stage in the dextral tension veins and the formation of vein- type sulfide and breccia mineralization in the dextral compression and torsion structure, and associated with the silicification zone. In the late stage of ore- forming fluid, carbonation is the most common alteration type. The results of stable isotopes (C, H, O, S) indicate that the ore- bearing hydrothermal fluid is the product of miscibility of highly evolved magmatic water and meteoric water. Some of the carbon may originate from the mantle and is related to magmatism. The obvious negative δ34S (-11.2~-24.8‰) indicates that the ore- forming hydrothermal fluid presents high oxygen fugacity. The composition of radioisotopes (helium—lead) suggests that the lead and helium in ore- forming materials may be partially derived from mantle fluids. Therefore, the formation of structure—mineralization—alteration of Zhongshangou gold deposit may be related to magmatism, and it is a medium-temperature and medium-sulfur hydrothermal deposit related to mantle branch structure.