The correlation between fine Particulate Matters （ PM2.5 ） and Fine-mode Aerosol Optical Depth （ AODf ） is established. AODf is obtained from product of Aerosol Optical Depth （ AOD） and fine-mode fraction at Beijing site belonging to the AErosol RO-botic NETwork （ AERONET） in January 2013. And then we compare estimation with observation of PM2.5 from 1 to 15 February

2013. The results show that the developed correction method is effective to estimate PM2.5 during haze

with root-mean-square error of 50 μg / m3 at a mean level of 85 μg/m3 . The relationship between AODf and PM2.5 is obviously better than that of AOD and PM2.5 . It is also found that when the relative humidity is higher than 80%

the humidity correction on AOD-PM2.5 correlation is limited

and the vertical correction cannot improve the correlation during haze.