The aramid fiber(AF)and aramid pulp(AP) were incorporated into the rigid polyurethane foam(RPUF) and the influence of AF and AP dosage on the cell structure, compressive strength, thermal properties of the RPUF was investigated. The results show that compressive strength of the foams increased and then decreased with the contents of AF and AP. The compressive strength at the bottom of the foam reached the maximum value of 0.394 and 0.353MPa respectively when the adding contents of AF and AP was 6wt%,whose microstructure revealed finer and more homogeneous cell size distribution.The AF and AP dispersed and situated within the cellular skeleton of the foams,and it contributed to the property enhancement through forming a good adhesion with the resin. The addition of AF and AP was helpful for improving the thermal stability of the foam.AF reinforced foams showed superior thermal stability compared with AP.