The characteristics of self-denitrification in biobriquettes are studied experimentally. To enhance effective utilization of low-grade coals, and to control emission of environmental pollutants from combustion, a new artificial solid fuel, a biobriquette with a self-denitrification function, is developed. It was produced by the mixture of low-grade coal, cornstalk as biomass and pulp black liquid as denitrificazer under a high compression pressure condition. Both experiments of pyrolysis and combustion were performed in order to reveal the mechanism of nitrogen-oxide formation and denitrification of the biobriquette. It is found that the release fraction of fuel-N is raised with increasing pyrolysis temperature in both coal and biomass. The release fraction of fuel-N in biomass is much higher than coal at the same pyrolysis temperature. The conversion fraction of fuel-N to NO slightly ascends and the fraction to N2O slowly descends with increasing furnace temperature, but the sum of conversion fraction of fuel-N to NO and N2O appears to be independent of furnace temperature. The denitrification process of the biobriquette with the pulp black liquid appears to proceed as two stages, namely the volatile combustion stage and the char combustion stage. Denitrification mainly happens in the char combustion stage. A denitrification efficiency of 40% can be obtained in the biobriquette combustion with a pulp black liquid of 10 mass%. Finally, it is confirmed for the first time that the pulp black liquid has significant denitrification capabilities in the biobriquette combustion.