Hydrothermal treatment of plant biomass using subcritical water is one of the pretreatment methods for producing valuable chemicals such as D-glucose for producing bio-alcohol. However, this treatment causes side reactions and produces by-products such as organic acids and furans which may inhibit the production of alcohols in the following step. In this study, the adsorption process is applied to remove by-products from products solution. As adsorbents, Cellufine A-200, A-800, DIAION WA21J, and activated carbon were used. Among them, Cellufine A-200 selectively adsorbed organic acids and activated carbon showed the best adsorption performance for furans. DIAION WA21J adsorbed both organic acids and furans.