Abstract: A 320 nm ultraviolet laser with Pr:YLF crystal was pumped by different wavelength blue laser diode was designed and double end pumping mode was adopted. The structure of the laser is V-folded cavity. A 444 nm blue laser diode with pump power of 3 W and a 469 nm blue laser diode with pump power of 1.4 W was used as pump source. The Pr:YLF crystal has a length of 12 mm and a doping concentration of 0.3%. The phase-matched LBO crystal was used as frequency doubling crystal. By optimizing the resonator parameters, when the incident pump power is 5700 mW, the maximum output power of 320 nm ultraviolet continuous laser with 1005 mW is output, and the optical conversion efficiency is about 17.6%.