The effect of deep freezing on the fracture behaviors of solid polymers has been investigated experimentally as a fundamental study of industrial cryogenic crushing operation.The mechanical properties of polymethyl methacrylate (PMMA) and polyvinyl chloride (PVC) are found to be critically dependent on the temperature (-180∼+120°C) at which they are deformed, as shown by the following equations (1)∼(3), but are independent of the strain-rate at which they are deformed, in the range of crosshead speed about 0.5 to 500mm/min. The values of true breaking stress σBc, and breaking strain eBc at the ductile-brittle fracture transition temperature Tc are the material-constants.σB/σBc={1-e-(Tc/T)2}/(1-e-1) (1)eBc/eB={1-e-(Tc/T)3}/(1-e-1) (2)ey=eB0=(1-e-1)·eBc=0.6321eBc (3)