In this article, shape memory polyurethane fibers were prepared by wet spinning. The shape memory switching temperature was the melting temperature of soft segment polycaprolactone phase at 36.20 degrees C. The fibers' mechanical properties, especially the shape memory properties, were explicitly characterized and compared with that from some commercialized polyurethane elastic fibers. The prepared 40 denier shape memory fiber (SMF) had a tenacity of about 0.93-98 cN/dtex, and the strain at break ranged from 85-115%. At ambient temperature, the modulus of SMF was in general larger than those of the Elaspan and Newstar fibers. The SMF had a shape fixity ratio of more than 80% and recovery ratio more than 95% under thermal drawing and recovery cyclic tensile testing. The results from differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) were used to illustrate the mechanism governing the mechanical properties and shape memory effect especially. (c) 2007 Wiley Periodicals,