Abstract: Boron carbon nitride（BCN） thin films were deposited on Si（100） and quartz substrates by pulsed laser deposition.X-ray diffraction（XRD）,Fourier-transform infrared（FTIR） spectroscopy,X-ray photoelectron spectroscopy（XPS） and ultraviolet-visible spectrophotometer were used to characterize the BCN thin films.The effects of the laser energy density on the film deposition rate,composition,structure and optical properties were investigated.FTIR and XPS analyses indicated the as-deposited BCN films contained B-C,N-C and B-N chemical bonds with B-C-N atomic hybridization.The film deposition rate increased with increasing laser energy density from 1 to 6 J/cm².Meanwhile,the nitrogen content increased from 7.2 to 15 at.% and the optical band gap（E_g） decreased from 4.02 to 3.82 eV with increasing laser energy density.The behavior of E_g is mainly related to the increase of carbon content in the BCN thin films.