B-C-N compounds with different structures were synthesized by chemical reaction between Boracic acid and melamine, combined with heat treatment under vacuum and high pressure. An amorphous B-C-N precursor was prepared at 1273K under 10-3Pa. This amorphous B-C-N behaves as an insulator below 920K, and transforms into semiconductor above 920K. The B-C-N semiconductor shows different conductivity-temperature relationship in the temperature ranges of 973—1003K and 1013—1073K, and has conductivity activation energy of 0.34eV in the former range and 1.10eV in the latter range, indicating that conductivity mechanism of the B-C-N amorphous semiconductor is different in the two temperature ranges. Annealed for 40min. at 1473K under 3.5GPa, the amorphous B-C-N precursor crystallizes into hexagonal B0.44C0.27N0.29(h-BCN) compound with lattice constants of a=0.2515nm and c=0.6684nm. Four strong Raman scattering peaks were observed at 1330,1364,1588 and 1617cm-1 in the h-BCN, of which the peaks located at 1330 and 1617cm-1 are considered as characteristic Raman peaks of the h-BCN.