Canteen waste was hydrothermal pretreated to investigate the characters of degreasing, hydrolysis and digestibility by biochemical methane assays. Liquidization and hydrolysis were enhanced in hydrothermal pretreatment. pH of hydrolysate decreased, and SCOD and VFA increased significantly followed by increasing hydrothermal temperature. Floatable grease increased to appropriate ratio for removal, and digestion process completed in 4 days to 6 days with double degradation rate after pretreatment at 150 degrees C for 60 minutes. The 4-day incubation biogas yield was maximum after pretreatment at 170 degrees C, and the methane potential, however, was decreased at higher pretreatment temperature. Energy consumption of optimized pretreatment was recoverable with energy balance analysis.