Abstract: The gas jet purifying device makes use of differential static pressure to circulate purifying liquid, mixes liquid with gas through entraining and jetting, and finally realizes purifying of gas. The liquid level must be high enough to assure the gravity circulation of liquid. In the jet pipe, the flowing gas holds a turbulent state. The two phase flow of gas and liquid should reach the critical speed necessary for a continuous jet. Some defects of traditional pump feed circulation are overcome. It is especially suitable for systems using erosive substances（such as acid,alkali） as purifying liquid.