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In this study, the nanometer lignin was mixed with the silicon nitride staring powders, and the mixed powder was pyrolyzed and sintered to obtain a novel composite material. The microstructure and composition of the novel ceramic composite were examined using Raman spectroscopy, electron dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy and field emission scanning electron microscopy. Surprisingly, nitride-doped graphene quantum dots (N-GQDs), derived from nanometer lignin, was found around silicon nitride columnar grains in the form of overlayers. Meanwhile, the test results showed that the formation of N-GQDs overlayer significantly improved the bending strength and fracture toughness of silicon nitride ceramic. This work presents a promising approach for fabricating high-performance ceramic composites by adding nanometer lignin precursors to silicon nitride ceramic matrix.