The Aerosol extinction coefficient is of crucial importance for atmospheric visibility and climate change.The aerosol extinction coefficient is measured based on the cavity ring down spectrometer using 532 nm pulsed laser.The detection limit of the aerosol extinction spectrometer is 0.3 Mm^-1. Pure CO₂, pure Freon R134, and different concentration NO₂ are used for full scale calibration. Comparative field measurement of aerosol extinction using aerosol extinction spectrometer, nephelometer and aethalometer are carried out, and the data are in good agreement.