Abstract: Based on Terra/MODIS MOD021KM data from September 1,2014 to May 31,2015,as well as deep blue algorithm and look-up-table methods,aerosol optical depths (AOD) over Jing-Jin-Ji region were retrieved with the spatial resolution of 1 km,the results were compared with NASA products and CE-318 measurements.The results show that the retrieved AODs have higher spatial resolution and relatively good agreements with the products of MOD 04_L2 (10 km×10 km) and MOD 04_3K (3 km×3 km) .The mean absolute error between retrieved AODs and those observed by CE-318 sun-photometer at Shijiazhuang site is about 0.07,with a high correlation coefficient of 0.98.When Terra passed the territory,mean errors of retrieved AOD compared with MOD 04_L2 and MOD 04_3K products were around 0.06 and 0.03,respectively.Further relationship analysis on the spatial contributions of retrieved AODs and the mass concentrations of PM_2.5 and PM₁₀ over Hebei province indicated that the correlation coefficients between AOD and PM_2.5 and PM₁₀ are 0.745 and 0.663,respectively,suggesting that the retrieved AODs with the resolution of 1 km could effectively reflect the mass concentrations of PM_2.5 and PM₁₀.