Abstract: Cubic boron nitride (cBN) was coated by SiO₂ using the sol-gel method, and then polycrystalline cubic boron nitride (PcBN) was prepared by spark plasma sintering (SPS) under the pressure of 100 MPa at 1 700℃ for 10 min using Al powder, B₄C powder and carbon powder as sintering additives. The sintering ability, phase composition, micro-morphology, mechanical properties of PcBN and the cutting performance of fabricated cutter were studied. The results show that the combined effect of sintering additive, in-situ reaction and activation of cBN particles promoted the densification of PcBN, obtaining a relative density of 97%. The main crystalline phase of PcBN was cBN, and also included SiO₂, Al₃BC₃ and SiC phases. The hardness of PcBN was (38±3.5) GPa, and bending strength was (425±23) MPa. At the same cutting speed, the breakdown area of the front surface and the wear band length of the rear surface of cutter made of the obtained PcBN were smaller than those of PcBN (BN11) cutter fabricated by a Japanes renowned company. When the cutting speed increased from 200 m·min^-1 to 400 m·min^-1, the wear degree of cutter made from PcBN was slighter than that of BN11 cutter, indicating the cutting performance of cutter made from PcBN prepared by SPS was better than that of BN11 cutter.