Graphene oxides (GO) that has a band gap of 3.2 eV is widely applied to remove color pollutants in water using the adsorption method. Besides, GO is also widely used as a supporting material in nanocomposites for photocatalytic applications. In this study, we carried out adsorption tests of methylene blue (MB) by GO in dark conditions and with UV-A light irradiation. The adsorption tests were carried out by mixing the GO dispersion with MB solution, then stirring for a certain period of time. During the process, samples sampling was carried out at a certain time to estimate concentration of the MB permeate. The adsorption tests were carried out in dark conditions (without irradiation) and with UV-A light irradiation. The results showed an improvement of adsorption ability of GO in reducing MB permeate concentration from 74% to 92% under the UV-A light irradiation. The process of adsorption without and under UV irradiation successively also shows an increasing reduction of concentration of MB in water