In this paper, a titanium diboride ceramic was produced by the hot pressing sintering method. The effects of hot pressing parameters on the TiB2 ceramic microstructure and mechanical properties were studied. The bending strength and fracture toughness were measured by three point bending testing and single edge notched bending tests (SENB), respectively. The microstructure features of the TiB2 sintered material were revealed by means of SEM and TEM. The results show that the TiB2 grain size increases quickly with the increasing temperature and time during hot pressing sintering. The density and the TiB2 grain size have a great influence on the mechanical properties. The bending strength decreases with increasing TiB2 grain size, whilst the fracture toughness increases.