Taking cubic boron nitride (cBN), TiN, and aluminum as raw materials, polycrystalline cubic boron nitride (PcBN) composites by sintering at 1 500℃ and 5.5 GPa. The effect of the mass ratio (21:4,17:8,13:12,9:16) of TiN to Al in the TiN-Al system binder on the phase composition, microstructure, hardness and wear resistance of PcBN composites was studied. The results show that PcBN composite was mainly composed of BN, TiB2, TiN, AlN and Al2O3 phases. With increasing the aluminum content in the binder, the structure of PcBN composite became denser, and the porosity decreased; the hardness and wear ratio first increased and then decreased. When the mass ratio of TiN to Al was 17:8, the comprehensive property was the best with the largest hardness and wear ratio of 35.8 GPa and 7 500, respectively, and the relatively small porosity of 0.83%.