Four Ti(C, N)-based cermets was fabricated from different size of ceramic powder by the conventional powder metallurgy technique. Microstructure, fracture surfaces and crack propagation path of samples were observed by SEM, and mechanical properties such as transverse rupture strength, hardness and fracture toughness were measured. Results show that with the refinement of the raw TiC/TiN powders, the black cores and ceramic grains tend to be finer, the gains with white core-grey rim structure obviously increase, and the microstructure of cermet becomes inhomogeneous. The cermets fabricated from fine powders possess higher porosities. Compared with the cermets made from micron ceramic powders, the cermets fabricated from ceramic powders containing nano powder possess higher transverse rupture strength and lower fracture toughness. When the cermet is fabricated from micron TiC/nano TiN powders, its combination property is the best.