This invention discloses a ceramic containing cubic nitride powder. The ceramic is composed of: gamma-Si3N4 5-100 wt.%, at least one of Al2O3, ZrO2, alpha- or beta-Si3N4, SiC, BN and AlN 0-95 wt.%, and at least one of Y2O3, Al2O3 and La2O (sintering aid) 0-10 wt.%. The ceramic is prepared by: preparing the raw materials, dry-cooling, grinding by isostatic cool pressing, dry-pressing, assembling the sintering chamber, and sintering under an ultrahigh pressure. The method has such advantages as simple process, easy operation, low sintering temperature, and short sintering time. The ceramic has such advantages as high compactness, uniform microstructure, and good mechanical properties, and can be used in the fields of mechanics, chemical engineering, aviation and photoelectronics.