The preparation of powder polycarboxylate superplasticizer by centrifugal spray drying process was discussed. The powder solid content(by mass) of the product can reach 99%. Through infrared spectroscopy the carbonyl group has been shown to be partly decomposed during the drying process which has only limited influence on the performance of the powder with the result that its performance is at the same level compared to the liquid superplasticizer. Based on single factor experiments, the major parameters affecting the drying process were discussed and the appropriate process conditions were obtained, e.g. the import air temperature of drying chamber must be controlled at 180220℃；the spraydrying feed temperature controlled at 2040℃, and solid content of polycarboxylate superplasticizer fed is in the range of 20% to 60%.