Abstract: In order to get shorter pulse width to improve time resolution,femtosecond pulse was compressed by using two prisms and a reflective mirror.Femtosecond pulse was measured with a home-made second-harmonic generation frequency-resolved optical gating.The temporal width of input pulse was 89fs,the time-bandwidth product was 0.9096,the minimum error was 2.4‰ and the average power of the input light was about 480mW.The width of compressed pulse was 22fs,the time-bandwidth product was 0.44203,the minimum error was 1.1‰ and the average power of the output light was about 250mW.The compression ratio was 4:1,which was higher than that in the related report.The experimental results indicate that the compressing device is valid and the result is useful for getting shorter pulses.