To solve the problems of single parame ter,high measurement uncertainty and incomplete traceability system existing in the aerosol optical c haracteristic measurement instrument, we combine photo-acoustic spectroscopy (PAS) with optical cavity ring down spec troscopy (CRDS) and realize simultaneous measurement of aerosol extinction,absorption and scattering coeffi cients with the proposed online and high-precision measurement device.The device with NO_2stand ard gas material calibration can be applied in the measurement of the atmospheric aerosol optical properties,wit h the measuring relative error,repeatability and uncertainty less than 4%,0.2% a nd 2.8% (k=2) respectively.Compared with the aethalometer and nephelometer,the E_n values of extinct ion coefficient,absorption coefficient and scattering coefficient of the device are all less than 1,which indicates good consiste ncy and stability.Experimental results show that the device has the ability to measure multi-parameter and the measurement results are accurate and reliable,which can be used for the real-time measurement of the optical pr operties of atmospheric aerosol and for the calibration of other measurement instruments to provide traceability.