The sulphuration characteristics of limestone and man-made sulfur sorbent have been studied by means of experiments under varied temperature (350−1050°C) and calcium-sulfur mol ratios (0.72−3.7).Making use of Fe203 NaCl, Si02 and MgO as the additive, we have analyzed theoretically and researched experimentally their catalytic mechanism and characteristic when limestone was used as sulfur sorbent. The regularity which the additives effect on limestone's sulphuration and optimal adding quantity range of the additives have been obtained respectively. According to the regularity that temperature effects on sulfur fixing efficiency, a model of predicting the ηs (sulfur fixing efficiency for moulded coal) has been proposed . In addition, a great deal of experiments have been carried out on compounding sulfur sorbent with some kinds of substance. These can provide a basis for compounding reasonably sulfur sorbent and improving the ηs.