Using crystal waste of industrial production as material, the method was adopt in order to separate silica and cerium. Using ammonia water as setting agent, the research on purity and quality was studied, such as concentration of ammonia water, setting time, pH value, heating temperature and time. The result was indicated that ammonia water content is 6mol/L, pH value is 8, setting time is 30 minute, heating temperature is 450, heating time is 2 hours, and thus the content is reached to actual value.