Cu-TiB₂ composites were prepared by combining in situ reaction and hot-pressing under different temperatures after ball-milling of the mixture powders of Cu, Ti and B. The reaction process of Cu-Ti-B system is discussed in detail. By means of XRD, SEM, EDS and XPS, it was determined that TiB₂ nano-particles generated by in situ reaction in Cu-matrix. According to making the calibration curve of TiB₂ and Cu by XRD, the concrete synthesis rate of TiB₂ in Cu-matrix under different sintering temperature by external standard method was confirmed. The experiments show that under certain temperature range, the higher the temperature is, the higher synthesis rate is, and the best synthesis rate of TiB₂ is 99.27% at 1000℃. Cu-1.5wt%TiB₂ prepared at 1000℃had the best properties, Vickers hardness(HV), electric conductivity(EC), flexure strength(FS), thermal expansivity(TE) and thermal conductivity(TC) at 100℃ were 125.68MPa, 80.1 % IACS, 755.2 MPa, 9.3×10_-6 / K and 260 W/mK, respectively.