A novel tabletop Ti: Sapphire/ KrF ultrashort pulse laser system was developed for laser matter interaction researches in CIAE. The characterization and optimization of output parameters of this UV shortpulse laser system were described in this letter. With the use and properly choosing parameters of off axis amplification scheme and prism pair pulse compressor, the laser system achieved in an output of 50mJ energy, 220fs pulse duration at 248nm wavelength, and the beam was focused to an intensity of 1017W/cm2 on target.