Photonic crystal fiber is a good nonlinear medium which plays an important role in generating supercontinuum. Deep ultraviolet supercontinuum light sources in many applications have urgent needs, but due to the influence of experimental conditions and fiber parameters, using highly nonlinear photonic crystal fiber produced deep ultraviolet supercontinuum (<280 nm) has reported less. In this paper, we study the frequency conversion of high nonlinear photonic crystal fiber in the deep ultraviolet region, and analyze its physical mechanism through theoretical and experimental. Photonic crystal fiber with length of 1.45 m and the zero dispersion wavelength of 825 nm made in our lab is pumped by the femtosecond Ti: sapphire laser in the abnormal region and the dependences of deep ultraviolet supercontinuum on the different pump powers and pump wavelengths are investigated. The experiment results show that when the pump wavelength is fixed to 860 nm, the broadening range of deep ultraviolet supercontinuum is gradually broadened with the increase of pump power; when the pump power is fixed to 0.4 W, the cross-phase modulation between the solitons and the dispersive waves can effectively extend the fundamental mode deep ultraviolet supercontinuum into the wavelength of 212 nm. The increase of pump wavelength not only broadens supercontinuum range but also greatly improves the conversion efficiency of deep ultraviolet supercontinuum.