The chirped pulse amplification technique was used to amplify femtosecond light pulses in the laser material Cr:LiSAF. The amplifier produces approximately 200 mJ chirped ps pulses at a repetition rate of 0.5 Hz. And after recompression, femtosecond light pulses with a pulse duration of roughly 350fs and a maximum peak power approaching to 0.04 TW are put out.