SiC-Si3N4 composites were prepared by mixing $alpha$-Si3N4 powder to $alpha$-SiC powder in the range of 10 to 30 vol% with 10vol% interval. 6wg% Al2O3 and 6wt% Y2O3 were respectively added as sintering aids. Hot pressing was performed at 1,80$0^{circ}C$ for 1 hour with 25 MPa pressure. In the case of adding 20vol% of $alpha$-Si3N4 powder the relative density to theoretical value and the flexural strength were 99.1% and 34,420 MPa respectively and the worn amount was 2.09$ imes$10-3 mm2 which were the highest values in the all range of he composition. Although the composite containig 10 vol% of $alpha$-Si3N4 powder showed the highest fracture toughness(KIC) of 4.65MN/m3/2 the reduction of the wear resistance in this composite is likely to be affected by the homogeneity and the uniformity of the grain coalescence and growth during the sintering process.