Abstract: To study the effect of strain rate on mechanical properties of polysulfone,tensile tests at different strain rates were performed,and the shape changes of samples during testing were recorded by camera also.The results show that the mechanical properties of the polysulfone were obviously ratedependent.Cracks induced by bubbles impurityies and other crack initiations propagated to form coin cracks along respective surfaces and resulted in tensile failure (single crack initiation) or tensile-shear failure (splitlevel multi-crack initiations).