In this present study, thermal hydrolysis pre-treatment improved the hydrolysis of organic solids and the solid-liquid separation ability of MB, making it possible to obtain a long solid retention time (SRT) and high degradation ratio in anaerobic sequencing batch reactor (ASBR). Biofilm carriers were introduced into ASBR to prolong the mean cell retention time (MCRT). The biofilm system operated at an organic loading rate (OLR) of 3.5-5 gVS L(reactor)(-1) day(-1) and a hydraulic retention time (HRT) of 13.3 days. The biofilm carriers provided perfect Conditions for microbe retention and growth, improving the digestion efficiency, The MCRT was 89-150 days and SRT was 24-36 days, with the methane yield of 330-370 mL g(-1) VS(added) and VS(d) of 62-70%. Meanwhile, due to the mass-transport resistance and high microbe density of the biofilm, the system show high stability. Therefore, the biofilm system provided an approach for a highly efficient anaerobic digestion of municipal biowaste. (C) 2009 Elsevier Ltd. All rights reserved.