Abstract: Using the data of multiband solar direct radiative intensity observed in July 1980 to July 1981 at Peking University, the variation of the atmospheric transparent spectrum and the Angstrom turbidity were analysed. According to the change of the aerosols' optical depth with wavelength, it was shown, in about 88% cases, the size distribution of the aerosols were the same or very close to the Junge distribution. Usually, the parameter,of the Junge distribution and the Angstrom turbidity β have a inverse relation.