Yata gold deposit is a typical sediment-hosted disseminated gold deposit in southwestern Guizhou Province. Based on the data from fluid inclusions, the authors discuss the temperature and pressure conditions and the fluid evolution in the ore-forming process. The results from petrographic observation and fluid inclusion microthermometry study of gangue minerals in different stages are described in this paper. Based on the comparison of characteristics of CO₂-rich fluids in different types of gold deposits, we conclude that CO₂-rich fluid in Carlin-type gold deposits in southwestern Guizhou may play a role in the transportation of gold, and that phase separation between CO₂ and H₂O could be the cause for gold deposition.