Abstract: An improved testing unit of gas adsorption in solid medium is developed based on the advantages of helium porosimeter commonly used in petroleum industry and that of volumetric gas adsorption test meter widely used in petrochemical industry.The temperature testing and control system can accurately measure and control temperatures ranging from15℃to100℃with an absolute error no larger than±0.1℃;and the pressure testing system can accurately measure pressure of the system within a range of0to60MPa with an absolute error no larger than0.001MPa.The volume testing system is used to store and absorb core gas,can self correct the volume of adsorption dead space,and can accurately measure cylindrical core with a diameter of50mm and a height of20to200mm,and isotherm adsorp-tion data of various single or multi components gas adsorp-tion systems.