Abstract: A thermometric titration method was applied for the determination of sulfate in FGD gypsum. The sample was mixed with hydrochloric acid solution,and then heated to boiling for 10 min. After cooling to room temperature,the solution was titrated with barium chloride solution by temperature titrator. Under optimized condition,the measured results of 72.8%-93.6% sulphate by this method was in agreement with that by standard method,giving RSD′s in the range of 0.30%-0.95%. The recovery rates measured by standard addition method were in the range of 96.8%-102%.