Novel thermotropic liquid crystalline polyurethane was prepared from 4,4'-Bis(6-hydroxyalkoxy)-benzylideneaniline and diisocyanate. The polymer was obtained in relatively high yield(87%). Polyurethane was estimated to be 6.5×104 by the measurement of GPC in DMF eluent using polystyrene standards. FT-IR spectroscopy and nuclear magnetic resonance(1H-NMR)spectroscopy. Optical and thermal methods reveal that this polyurethane exhibits monotropic mesomorphic behavior. The polyurethane exhibits good thermal stability and mechanical properties.