Powder metallurgy (PM) Ti6Al4V alloy was prepared from HDH alloy powder by vacuum pressureless sintering. To study its high-temperature deformation behaviour, isothermal compression testing was carried out with temperature range of 900-1050°C, strain rate range of 0.01-10 s −1 , and compression ratio of 60%. Based on the hot deformation data, the corresponding constitutive equation and hot processing map were clarified. The deformation activation energy for PM Ti6Al4V alloy was 606.5 kJ mol −1 . Its deformation instability zone was very small, locating in the range of 960∼990°C with strain rate >1 s −1 . PM Ti6Al4V alloy had large hot working window and good hot workability. The ideal hot processing domain was at 970-990°C and 0.05-0.01 s −1 . Besides, the domain at 1000-1040°C and 1-10 s −1 was also suitable for hot processing. This study proposed an effective guidance for the hot deformation (e.g. forging, extrusion, rolling) of PM Ti6Al4V alloy.