Abstract: The paper has outlined two kinds of typical apparatus used for static and dynamic methods. The results obtained by two kinds of apparatus are comparatively consistent. The specific surface measured by this method is total surface area. In case of the use of nitrogen adsorbate, single point method can be adopted. In case of the measure of small specific surface, the adsorbate with low saturation vapour pressure should be shosen, e. g. argon, krypton, etc.. Consistent results have been obtained by adopting different adsorbates. A minimum specific surface of 0.001m²/g can be measured by using krypton adsorbate.