Abstract: Aiming at design flaws of cylinder pressure type biogas tank which was widely promoted in rural areas of Sichuan province，considering sealing principle of cylinder pressure vessel well ring，a new device for common well ring of household biogas tank，which has strong practicability，was designed in order to achieve self-built pool farmer could conveniently test pressure and eliminate residue. It could really play better benefits for purpose of construction of biogas digesters.