ZrN-Si 3 N 4 composite powder with low cost from zircon was prepared by carbothermal reduction-nitridation process. The influence of mass ratio of C to ZrSiO 4 (m(C)/m(ZrSiO 4 )) and soaking time on phase composition and microstructure of the products was studied by means of XRD and SEM-EDS. The formation process of ZrN-Si 3 N 4 composite powder was also analyzed in detail. The results show that with the increase of m(C)/m(ZrSiO 4 ) and soaking time, the formation of Si 3 N 4 and ZrN can be promoted obviously. The ZrN-Si 3 N 4 composite powder with size of 1–2 μm can be obtained at 1 773 K for 12 h when m(C)/m(ZrSiO 4 ) is 0.4.