Continuously tunable second harmonic generation of 294.8-282.5 nm was obtained by Q-switched YAG laser pumped Rh·6G dye laser in a 45°cut β-BaB2O4 (BBO) crystal. The output energy of the harmonic wave is about 8mJ around 285 nm. The continuously tunable output over the range of 230.8-223.2 nm was also obtained by the sum frequency mixing between the residual pump fundamental wave (1064nm) and the second harmonic wave of Rh 6G dye laser in an other 45°cut BBO crystal. The sum frequency output energy is about 120 μJ around 226 nm, the corresponding peak power is 12 kW. The key techniques of the sura frequency generation were indicated.