Several nano-composite Ti(C, N)-based cermets were produced by vacuum sintering and subsequently heat-treated with hot isostatic pressing (HIP) in Ar. The influence of nano powder additions on the microstructures and properties of cermets has been studied It was found that, with increasing nano powder additions, the microstructures became finer and even, the amount of small grains with inner-rim, outer-rim and those with “white core-gray rim” increased. When nano TiC and TiN additions accounted for 20wt% of the amount of TiC and TiN, the samples exhibited the best properties. Some nano particles were found to distribute at (along?) the grain boundaries of cermets, which strengthened the grain boundaries and improved the mechanical properties of Ti(C, N)-based cermets.