Ground-based measurements of the aerosol optical thickness at an island are taken from October 17, 2000 to November 2, 2000 to achieve information of ocean aerosol properties with a multibands sunphotometer. In this paper, the calibration of sun photometer, the calculation of atmospheric aerosol optical thickness and the Angstrom parameters a and β obtained from aerosol optical thickness are discussed. The results show that in Yellow Sea the atmospheric aerosol consists of nature aerosol and aerosol optical thickness is approximately 0.1 in the most cases. Generally, Angstrom parameter a is nearly 1.2 and β is nearly 0.05.