Abstract: This treatise introduces a method for purifying hydrogen by activated carbon adsorption at low temperature(liquid nitrogen as cooling agent) instead of high pure hydrogen generator, and a catalytic method for pyrifying carrier gas and combustion promotion gas, thus raising the sensitivity of gas chromatography SP-2305 E. The following are reached: minimum limit of detection -0.02 ppm, relative deviation -1.5%, coefficient of variation -4.9%, analytic period -10 seconds. In addition, this treatise has also made a comparison among the purification effects of the three catalysts and the sample storage times of the seven,sampling apparatuses of diffrent materials.