The sintering process of Ti(C, N)-based cermets is accompanied by a strong nitrogen decomposition. As an important process parameter, nitrogen partial pressure affects the “core-rim” structure and mechanical properties of Ti(C, N)-based cermets. Therefore, Ti(C, N)-based cermets can be prepared by using Ti(C, N) powders of different particle size, to be sintered at 0.5, 1.0, 1.5 kPa nitrogen partial pressure and different sintering temperatures, followed by a study on the effects of sintering nitrogen partial pressure, sintering temperature, and raw material particle size on the surface gradient microstructure and properties of Ti(C, N)-based cermets. The results show that the Ti(C, N)-based cermets form a rimless black-core aggregation layer under the effect of a nitriding process, in which the surface black-core aggregation layer becomes thicker with the increase of sintering nitrogen partial pressure. As the sintering temperature increases, the equilibrium nitrogen decomposition pressure of the sample increases, the driving force of the nitriding process weakens, and the black-core aggregation layer becomes thinner. In addition, the finer the particle size of Ti(C, N) raw material, the more intense the denitrification reaction before sintering densification, the more nitrogen loss of the sample, the lower the equilibrium nitrogen partial pressure, and thus the stronger the nitriding effect will be. With a nitrogen partial pressure of 1.5 kPa, columnar nitriding structure shows on the ceramic surface. And it is found that the surface of Ti(C, N)-based cermet, when sintered at a temperature of 1 470 ℃ with a nitrogen partial pressure of 1.5 kPa, has the thickest black core-rich layer and binder-rich layer, with a homogenous grain distribution and an average black-core grain size of 0.69 μm, where the sample is characterized with the best comprehensive properties.