Al powder, AlN powder, SiC whisker and sintering aids were wet-mixed, and then the specimens prepared with mixed powder were reacted by nitridation at 600∼1400$^{circ}C$ for 5 hrs. It was cleat that the higher nitridation and the more SiC whisker content were, the better bending strength was. The specimen of Al50/AlN50 reacted at 1400$^{circ}C$ for 5hrs had the nitridation percent of 97%, the shrinkage under 2%, and the relative density of 78%. And the maximum bending strength of reaction-bonded specimen was 250 MPa. The specimens completely nitrided were post-sintered at 1700, 1800 and 1900$^{circ}C$ for 2hrs. The post-sintered body had the shrinkage under 6% and the relative density of 86%. Because of the formation of solid solution between AlN and SiC whisker over 1800$^{circ}C$, the promotion of mechanical properties according to SiC whisker addition was not observed. The post-sintered body had the maximum bending strength of 195 MPa.