The technological processes of polystyrene (PS) initial granules and the hollow microshells formed on a vertical drop furnace from the granules dealt with a foamer are investigated. The initial granules are produced by one step emulsion techniques. Influences of phase ratio and stirring intensity on diameter distributions of initial granuales are discussed., and alcohol is selected as a foamer according to the boiling point and solubility. Then effects of temperatures、gaseous compositions and pressures inside the furnace on the quality of PS microshells fabricated from the granules are experimented. As a result, optimal conditions are selected to make PS microshells with outer diameters of 400～900m m , wall-thickness of 2~10m m and concentricity better than 95%.