Carbon quantum dots (CQDs) with fluorescent quantum yield of 48.10% were synthesized by solvothermal treatment using citric acid, urea and acetonitrile as carbon source, nitrogen dopant and solvent, respectively.CQDs have the average diameter of 13 nm and good dispersability in solvent.The as-prepared CQD acetonitrile solution, with average fluorescent lifetime of 10.99 ns and red-green-blue spectral composition ratio of 56.09%, exhibits bright blue fluorescence and shows an excitation wavelength-dependent behavior.White light-emitting diodes (LED) based on the CQD phosphors by using polyvinyl alcohol as encapsulating material are achieved with color coordinates of (0.33, 0.42) and correlated color temperature of 5 502 K, respectively, which demonstrates these CQDs have potential of application in the field of white LED.