kinetics and model for oxidation of CaS at 730—970℃ under pressure of 0.1 MPa and 1 MPa were investigated using TG technique. The oxidation product was analyzed by XRD spectra. The results showed that CaSO4 was the only product of oxidation of CaS. The conversion of CaS was enhanced by increasing pressure or temperature.The solid-solid reaction between CaS and CaSO4 was suppressed under pressure. The activation energy for chemical control and diffusion control was 73.08 kJ·mol-1 and 137.3 kJ·mol-1 and the pre-exponential factor for them was 3.905×10-5 and 0.1298 respectively. The oxidation rate of CaS was controlled by diffusion process.