Abstract: Studies on carbon-doped activated sintering of B4C powders with a specific surface area of 2. 53 m2/g obtained by jet milling are carried out. Effects of carbon-doping agent, carbon-doping content, and sintering temperature on B4C sintered density are also studied. The results show that carbon-doping promotes greatly the densification of B4C. Among three carbon-doping agents (black carbon, glucose, and phenolic resin), the addition of phenolic resin into B4C can obtain the highest sintered density. The density of B4C+3%C is 92. 1% TD at sintering temperature of 2 200 ℃ for 1 h and 94. 4% TD at 2 250 ℃, however 78. 6% TD and 82. 5% TD for pure B4C, respectively.