Abstract: In order to study the pressure pre-oxidation effect of refractory gold concentrates inside the pressure oxidation autoclave.The FLUENT software is used to simulate the flow field of refractory gold concentrates in pressure oxidation autoclave.GAMBIT is used to set up physical model of the flow field entity.Standard turbulence model and multiple reference frames are used to deal with the slurry stirring zone,and analyze the velocity filed,pressure field and temperature field distribution and flow rules of the slurry inside the autoclave.The results show that the model selected in the numerical simulation domain can accurately predict the velocity field,pressure field,density field and temperature field distribution of the slurry inside the autoclave.The slurry and oxygen are mixed evenly in the autoclave under the action of the mechanical stirring.The refractory gold concentrates can be fully pre-oxidized.