Hot plasticity of a nitrogen alloyed 25Cr-7Ni-4 Mo duplex stainless steel was investigated.The results indicate that thc main factors affecting the hot plasticity of duplex stainless steel are listed as follows:coalescent force of phase interface,microstructure,and the phase ratio and difference between the mechanicsl propertms of ferrite and austenite.The heat treatment and sulphur contents have a notable effect on the hot plasticity.The reasonable heat treatrnents and the irlcreased interfacial coalescent force will effectively enhance the hot plasticity of duplex stainless steel.