ZrC, Si and C powders were used as the sintering aids to enhance the densification and the mechanical properties of HfB2, due to the in-situ reaction between ZrC-Si-C at sintering temperature. Dense HfB2-ZrSi2-SiC ceramic composites have been fabricated by reactive spark plasma sintering at 1600 ℃ for 10 min under a pressure of 40 MPa. With the amount of ZrC-Si-C increasing, the Vickers hardness, the flexural strength and fracture toughness of the sintered samples increased first, then decreased. HfB2-10wt.% ZrC-Si-C composites showed the the best comprehensive mechanical properties. The Vickers hardness, flexural strength and fracture toughness of HfB2-10wt.% ZrC-Si-C composites were 26.80±1.2 GPa, 504±40 MPa and 4.66±0.21 MPa.m1/2, respectively.