This paper focuses on the reaction-bonded sintering of a Si3N4/intermetallic composite. The preparation process and the microstructural characterization of this composite with different initial contents of Ni3Al have been investigated. The effects of Ni3Al addition on the nitridation of silicon and the alpha --> beta phase transformation of Si3N4 formed, as well as the densification of the composite, also have been discussed. The addition of Ni3Al particles accelerates the nitriding rate of silicon and results in the formation of beta-Si3N4 phase at low temperature due to the reaction occurring between silicon and Ni3Al. Consequently, a completely nitrided and denser composite, compared with reaction-bonded sintered Si3N4, was obtained at low temperature. For comparison, pure silicon simultaneously processed was also investigated.