The direct reduction of zinc sulphide by hydrogen gas in presence of calcium oxide was investigated in the temperature range of 600-900℃. The reaction kinetics were determined by the thermo-gravimetric analysis technique with silica spring. The effects of temperature, additives, hydrogen flow rate and sample porosity were studied. The rates of reaction increased as temperature raising and more considerably increased markedly when calcium oxide was added as a sulphur scavenging agent. The effects of additives, Na₂CO₃and NaF on reaction rate were explained by the increase of initial reaction rates but their mechanism will be studied more extensively. Under these experimental conditions the rates of reaction were controlled by chemical reaction. It was discovered that the apparent activation energy of ZnS with 2CaO was about 26.3 ㎉.