The CE318 sun photometers are installed at 20 weather stations, which constituted the dust storm network for monitoring aerosol by the China Meteorological Administration since 2002. These measurements have not been well utilized because users are unfamiliar with the principles, data format and retrieval methodology of CE318 sun photometers. The impact of aerosol on climate and the application of data observed by photometers are discussed. At the same time, the retrieval method of sun photometer data, including the calibration and retrieval of aerosol optical depth and the quality control of data, is introduced. Combing with data at Tazhong, the Langley method for calculating the aerosol optical depth and the related issues are described.