The invention discloses a method for measuring the content of acid gas in polyethylene glycol dimethyl ether absorption solution. The method comprises the following steps of: heating the polyethylene glycol dimethyl ether absorption solution which is led out from a production system, cooling a great deal of mixture of water steam and flash steam which is generated due to heating after entering a color shape condenser, condensing the steam, recycling the dried gas through a gas-collecting bottle, later demarcating the volume amount thereof, and implementing chromatographic analysis and quantitative analysis of H2S to the dried gas for simultaneously measuring the substance compositions such as COS and the like which are difficult to be titrated out in the solution. By the analysis, the absorption condition and saturation of the solution in the production system are determined.