Polycrystalline diamond compact (PDC) cutter is widely used for mining and drilling bits in soft to medium hard formation. When drilling in hard and strong abrasive formation, the fast wear of polycrystalline diamond layer will result in the low service life of drilling bits. In order to improve the performance of PDC cutter, a high temperature and high pressure sintering method (5.5-6.0GPa, 1350-1500¡æ) was used in this paper by adding a certain proportion of graphene to the raw materials. A new type of high performance diamond composite (PDC-G) was successfully prepared. The microstructure, residual stress, hardness, wear resistance and electrical conductivity of the synthesized PDC-G were investigated. The results showed that when the ratio of different sized diamond powder was W_30/50:W_5/8:W_1/2=70:15:15, the wear resistance of PDC-G is the highest. Compared with the PDC without graphene addition, the hardness and wear resistance of PDC-G were increased by 75% and 35% respectively with the addition of 0.1wt% graphene. The electrical conductivity of polycrystalline diamond compact prepared by graphene strengthening is increased by 42 times. The Raman spectra of the samples treated by high temperature and high pressure indicated that there was no diamond crystal formed from graphen. The strengthening mechanism of PDC-G was mainly due to the lubricating effects of grapheme between diamond particles so that a more dense and uniform structure can be formed in the polycrystalline diamond layer after HTHP sintering.