Al4SiC4 bulk ceramics were synthesized by two steps: the calcination of aluminum, graphite powders and polycarbosilane (PCS), and a reaction hot-pressing using calcined powder. The present work confirmed that this process was an effective method for the preparation of Al4SiC4 ceramics having higher density and well-developed plate-like grains. Reaction paths in the present experiment were postulated on the basis of the analysis of DTA and XRD to the formation of Al4SiC4. The hot-pressing sintering temperatures influenced the phase compositions, microstructure and mechanical properties of Al4SiC4 ceramics prepared by this method. The microcracking mechanism was considered as the main reason of improving toughness according to the microstructure analysis. (c) 2005 Elsevier B.V. All rights reserved.