Abstract： High temperature tensile and compression experiments on high silicon austenitic stainless steel with different solidification modes and microstructure characteristics were adopted using the Gleeble3500 thermal simulation machine. The JMatPro software, OM(optical microscope), SEM/EDS(scanning electron microscope/energy dispersive spectrometer) and EPMA(electron probe)，were used to studied the thermoplastic variation of high silicon austenitic stainless steel. The results show that the ascast 6.0 wt.% Si samples solidified in FA mode (with ferrite as the first precipitated phase) have the worst thermoplasticity, due to the existence of precipitated phase and Weistierlike structure. After homogenization at 1150℃×12h, the solo austenitic structure of 6.0 wt.% Si samples was formed with the section shrinkage reached 76% and elongation 13%. The tensile fracture shows the ductile fracture characteristics and the thermoplasticity were significantly improved. After the 6.0 wt.% Si sample was homogenized at 1200℃×12h, a large amount of high temperature δ ferrite precipitates again, and the thermoplasticity decreases significantly as well the fracture took on the characteristics of intergranular fracture. Combined with hot compression experiments, DRX (dynamic recrystallization) is favored when a moderate amount of elliptical hightemperature δ ferrite is present in the 6.0 wt.% Si specimen.