A certain amount of H3BO3 was preheated at 120°C for 8h in order to obtain HBO2 for preparation of TiB2 powders by carbothermal reduction. The influence of different amounts of HBO2 (44.9–48.4 wt%), calcination temperature (1400–1800°C) and the variety of boron sources (H3BO3, HBO2 and B2O3) on the composition and microstructure of the product was investigated. The resultant powders were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Results showed that impurity-free TiB2 crystalline powders with the grain size of about 10.0μm could be successfully prepared at 1700°C for 30min in Ar atmosphere when the amount of HBO2 was 46.7wt%. Compared with control groups, grains of powders revealed better crystallinity and relatively finer particle size.