The shearing strain characteristic and microstructure of the semi-solid samples fabricated by sand mould and permanent mould were tested and compared by an improved compress testing equipment at different temperatures and loads. The results showed that the strain values of permanent mould s samples are much lower than sand mould s above 430℃ and the holding time is shorter when permanent mould’ s samples come into stage of the thixoforming. Compared with the microstructure of those samples after deformation at 481 ℃

the rate of volume fraction of producing liquid for the samples fabricated by permanent mould is slower than that of the sand mould samples at the initial stage

and the volume fractions of liquid increase rapidly and dendritic structures are becoming refining after 15 minutes.