Abstract: Sintering pressure is a key factor affecting the quality of PCBN. The pressure of industrial production is usually less than 6 GPa. In this test, through special design of press fittings, the assembly structure was optimized, and the high-precision temperature-controlled pressure-control system was used to study the sintering of low-content and fine-grained PCBN with the condition of more than 6 GPa. Through the volume wear ratio, CBN layer flatness and internal defect microstructure, the finished tool and E6 DCC500, Sumitomo Electric BNX20 turning test, to study the effect of ultra-high sintering pressure on low-content, fine-grained PCBN performance. The results show that the ultra-high sintering pressure can improve the wear resistance and flatness of PCBN and promote the diffusion sintering of CBN layer and cemented carbide layer.