The Blue emitting BCNO phosphors with high quantum yields were prepared at 625 °C using boron acid, melamine and hexamethy lenetetramine as raw materials. The BCNO phosphors have turbostratic boron nitride structure and consist of nanocrystalline with 5 nm in size. The emission and excitation spectra can be tuned by the contents of raw materials and sintering temperatures. The quantum yields of BCNO phosphors can be up to 99% with increasing boron acid. The FTIR spectra suggested the quantum yields can be improved with increasing strength of B-N and B-N-B bonds, and formation of B-O-B bonds, while it decreased with enhancement of C=C bonds. The emission decay curves indicated the decay process was related to two luminescence centers corresponding to carbon and oxygen impurity. In addition, the high temperature emission spectra disclosed that the nitrogen vacancy would participate in blue light emission process under certain heating temperature. The blue emitting BCNO phosphors with high quantum yields have great potential application in luminescence and display areas.