Single crystal cubic boron nitride(cBN) was heteroepitaxially grown on a seed crystal of diamond under static high pressure and high temperature of 5.5GPa and 1600–1700°C, respectively, for 10–100 hour. A temperature gradient method was employed for the crystal growth by using lithium boron nitride as a solvent. Initial growth feature of cBN crystal was found on the diamond seed surface after the growing time of 10 minutes. The nucleation sites of the crystals seem to be near the etch pits on the diamond surface which were introduced by the surface dissolution by the solvent for cBN growth. Two types of growth features, island and step growth were typically shown on the surface. It can be seen that grown crystal appearing as a (111) nitrogen face was exhibited with the step growth feature, while the (11n) face exhibited the island growth feature. Considering the growth process under constant P-T growing condition, growth rate of cBN crystal was significantly small as compared to that of diamond.