The high temperature gas flow field in a PVTM cyclone separator was measured by using a specially-fabricated，hemispherical five-hole pitot probe.The temperature of test air ranged from 293 K to 973 K and the cyclone inlet velocity from 16 m·s-1 to 36 m·s-1.The experimental results showed that the three-dimensional velocity components are good in axisymmetry and similarity along the axis but the tangential velocity value attenuated down the axis.The non-dimensional tangential velocity increased slightly and the dividing surface between inner and outer vortex also moved outwards with the increase of inlet velocity.With the rise of gas temperature，the tangential velocity decreased and its attenuation along the axis became greater.The effect of the gas temperature and inlet velocity can be reflected by a Reynolds number based on the axial flow in the vortex finder and an empirical expression for the maximum non-dimensional tangential velocity vs.Re was given.