The utility model belongs to the technical field of the chemical industry, the utility model discloses a gas absorption device who can positive and negative crush -cutting trades, can not realize in order to solve that positive negative pressure switches over at any time in the gaseous absorption process of separation gas mixture, inconvenient operation, the problem that wastes time and energy, the device includes the filled tower, the lower part of filled tower is equipped with the circulating slot, circulating slot upper portion is equipped with gas feed, add the alkali pipe, the circulatingslot lower part is equipped with the circulating pump, the export pipeline of circulating pump is connected with the spray set who installs on filled tower upper portion, the top of filled tower is equipped with the gas outlet, a root canal way of gas outlet is connected with the negative pressure water seal arrangement, the negative pressure water seal arrangement is connected with the fan, thefan is connected with first evacuation chimney, another root canal way of gas outlet is connected with the malleation water seal arrangement, the malleation water seal arrangement is connected with second evacuation chimney. The utility model discloses flow weak point, easy operation, small investment, can be at any time absorb and the negative pressure switched between absorbing in the malleation.