Characteristics of anaerobic granules before and after acclimation were studied using glucose as co-substrate. Removal efficiencies of 2,6-dinitrophenol (2,6-DNP) using two different co-substrates were investigated in two lab-scale UASB reactors. Granular sludge acclimatized to the wastewater containing 2,6-DNP through 3 months. After acclimation, SEM pictures of the granular biomass showed that Filamentous bacteria were the predominant bacteria on the surface of granules. Throughout the study of 2,6-DNP anaerobic degradation with different co-substrates, influent COD concentration was kept constant as about 2500 mg l-1. Maximum 2,6-DNP concentration was 170.0 mg l-1 and 2,6-DNP removal efficiencies were always more than 98.0% using glucose as co-substrate, keeping hydraulic retention time (HRT) as 35 h. When using sodium acetate as co-substrate and keeping HRT as 30 h, maximum 2,6-DNP concentration was up to 189.5 mg l-1 and over 99.2% 2,6-DNP removal efficiencies could be obtained.