Cu-TiB2 composites were prepared by combining in situ reaction and hot-pressing at different temperatures after ball-milling of the mixture powders of Cu, Ti and B. The reaction process of Cu-Ti-B system was discussed. By means of XRD, SEM, EDS and XPS, it is determined that TiB2 nano-particles are generated by in situ reaction in Cu-matrix. According to the calibration curve of TiB2 and Cu by XRD, the concrete synthesis rate of TiB2 in Cu-matrix at different sintering temperatures by external standard method was confirmed. The results show that in certain temperature range, the higher the temperature is, the higher the synthesis rate is, and the best synthesis rate of TiB2 is 99.27% at 1000 °C. Cu-1.5wt%TiB2 prepared at 1000 °C has the best properties, Its Vickers hardness (HV), electric conductivity (EC), flexure strength (FS), thermal expansivity (TE) and thermal conductivity (TC) at 100 °C are 125.68 MPa, 80.1% IACS, 755.2 MPa, 9.3×10−6 K−1 and 260 W/(m·K), respectively.