This paper study on surplus sludge of high pressure combined with thermal hydrolysis; investigate the start-up of ethanol-type fermentation. The results show that under the condition of HRT 3.6 d, the organic loading rate for 4.40kgVS/m3•d, the pH of acidogenic phase should be controlled in the scale of 4.0～4.5, the acidogenic phase could stable at the ethanol-type fermentation stage after the experiment lasting for 22d, the contractions of outlet sludge in VFA reached 3820～3980mg/L, in which the sum of ethanol and acetic could reach more than 72% VFA, the specific hydrogen production of acidogenic phase in this condition achieved 0.018 L•H2/g•VS.