The Chaima gold deposit is located on the northwest of the Fengtai ore concentration area in western Qinling. The gold mineralization could be divided into three stages：the early quartz-carbonate stage, the main quartz-carbonate-sulfide stage and the late quartz stage．Studies on fluid inclusions of each stage show that the ore-forming fluids are characterized by the intermediate-low salinity (4~10wt%NaCl) CO2-H2O system with intermediate temperature (240~300℃). The temperature and salinity are decreased from the early stage to the late stage. The diversity of fluid inclusion types in the main stage is resulted from the fluid immiscibility. By contrast with the Baguamiao and Simaoling gold deposits nearby, stable isotope studies indicate that ore-forming fluids of the three deposits are derived from the same deep source. The mineralization process of the Chaima gold deposit is closely related to brittle-ductile shear zone. The deep fluids flow upward inside the shear system, and mixed with the shallow fluids, and experience the replacement with country rocks. Finally, metallogenic materials concentrated and deposited within the structural dilation space due to the change of physical-chemical conditions.