This paper investigates the factors that influence the preparation of polysilicate aluminum ferric coagulant using solid wastes which containing and their microstructure and morphology. Four factors (basicity, nAl:nFe, polymerization temperature and reaction time) and three levels of response surface experiments were carried out, which regarded the transmittance as the evaluation index. Results showed that the optimum scheme when the basicity was 0.5, the nAl:nFe was 1.38, the polymerization temperature was 39.2℃, and the reaction time was 1.36hours. At the optimum theme, the predicted value of transmittance reaches 90.24%, and the relative error of all the verification experiments was 1.20%, which indicated the RSM optimization model is reliable. X-ray diffraction test indicates the formation of sodium chloride and new amorphous polymers from leachate. The infrared tests illustrates that a large amount of nonionic complex state (such as metal-hydroxyl groups) occurs between polysilicate acid and Al³⁺ and Fe³⁺. The TEM micrograph shows that the product presents a three-dimensional reticular structure, with high level of aggregation and branches. The thermogravimetric analysis shows that a substantial numbers of bound water and hydroxyl group were lost below 400℃, and the main chemical bonds in the products were broken at about 700℃. Strong endothermic peaks were presented correspondingly in the DSC diagram. The indexes test revealed that the coagulant presents good performance.