Abstract: Complex chemical industrial dewatering sludge, clay and adherent were chosen as the initial components for preparing raw aggregates of 3-6 mm in diameter used in wastewater treatment by drying, preheating, and firing processes. The effects of adherent quantity, sludge-to-clay ratio, preheating time and firing temperature on the performance of finished products were analyzed by measuring the bulk density, apparent density, specific surface area, crushing strength and wear rate. The optimal ratios of the components and the appropriate process were obtained as follows:adherent quantity 5%, sludge-to-clay ratio 4:6, preheating at 400 for 30 min, and firing temperature 1 140℃ according to the principles for making aggregates and the results of the orthogonal design method. The microstructures and characters of aggregates at different firing temperatures were observed by scanning electronic microscope.