A series of rigid polyurethane foams are synthesized via the reaction of isocyanate terminated polyimide prepolymers with polyether polyol. Deionized water and n-pentane are used for blowing agents. The prepolymers and polymers are characterized by conventional methods, and physical, mechanical and thermal properties are studied. The results show that in comparison to pure polyurethane foams, these rigid polymer foams exhibit improved thermal stability as well as good compressive property. SEM of the compressed body of rigid polyurethane-imide foams show that the destructive forms are open-type tear of the film and the breakdown of the cell body wall.