Objective Hexagonal boron nitride coatings were prepared on carbon fiber surface, in order to improve the oxidation resistance and high temperature resistant performance of the fiber, so as to broaden its application in the field of high temperature. Methods With boric acid, urea, ammonia and nitrogen gas as raw materials, a mixture of boric acid and urea solution was coated on the carbon fiber surface through impregnating method, and the coating was then placed in the ammonia and nitrogen atmosphere for high temperature pyrolysis. The morphology of the coating was observed by electronic microscope analysis to check whether the coating was well bonded with the carbon fiber. Fourier infrared spectra, X ray electronic energy spectrum and X-ray diffraction (XRD) were used to characterize the composition and structure of the coating. Results The coating on the surface of the carbon fiber was continuous and had good appearance. In the infrared spectrum, B—N key and B—N—B key characteristic peaks occurred at 1399, 799 cm-1 . In the X-ray diffraction pattern, (001) crystal plane and (004) crystal plane characteristic peaks of hexagonal boron nitride appeared at 43. 64° and 53. 93°, respectively. X-ray photoelectron analysis showed the existence of the four elements of O, B, C and N, and a B / N atom ratio of close to 1: 1. Conclusion H-BN coated carbon fiber was successfully prepared, and the coating was well bonded with the carbon fiber. The h-BN in the coating had good crystallinity and high purity, but the existence of a small amount of oxide had influence on the thermostability improvement of h-BN coated carbon fiber. More works have to be done to study how to further improve the purity of h-BN coatings.