On the basis of a large number of experiments, the influence of different kinds of additives on the desulfurization rate of absorbents is analyzed carefully. The surface area and intra-particle porosity of absorbents, which are calcined at high temperature, are also analyzed by mercury porosimeter. It is also reported that a good desulfurization result is obtained by the experiment in a chain grate furnace with the output capacity of 35t/h.