Abstract: Connecting the in-situ infrared characterization system of liquid adsorption with the infrared spectrometer is an important technical link to realize the in-situ infrared reaction process. In-situ infrared characterization process involves the adsorption liquid stored in the in-situ infrared characterization system of liquid adsorption, which can simultaneously complete the adsorption of some liquids with high boiling point by heating a set of temperature control operation, so as to achieve the monitoring of the structural changes during the adsorption reaction of the measured substances. A number of liquid adsorption tanks in the system can be set up, which can carry out a variety of liquid switching adsorption in the same experimental process to meet the adsorption of different liquid vapors by the substance under test, as well as the adsorption of liquid vapors by the substance under test and inert gas pretreatment or hydrogen reduction treatment on the solid surface. Finally, the reaction products were detected by the in-situ infrared monitoring, and the in-situ infrared characterization of the liquid adsorption was realized.