Abstract: Axial compression test was carried out by using a Gleeble-1500 thermal strain-stress simulator with spring steel 60Si2Mn as experimental material. The microstructural evolution and mechanical properties of the metal in semi-solid state are investigated during deformation. The results show that the flow stress of semi-solid samples at the liquid-solid zone is relative low, no other than 10 MPa. A strain-softening phenomenon appears with the deformation proceeding and the influence of deformation rate on the flow stress is comparative complex. The deformation behaviour of solid phase is different from that of liquid phase. The microstructural morphology has close relationship with deformation temperature, deformation degree and deformation rate.