Abstract: Taking waste liquor from steel-cleaning in hydrochloric acid and aluminum chloride as raw materials, A series of ferrous-modified polyaluminium chloride（Fe2 -PAC) were prepared firstly. Comprehensive analyses by FTIR ,X-ray diffraction and Electron-microscope, the results Indicated that Fe2 and PAC were not simply mixed, but has had certain interaction, its aggregate was stubby ,compacted, uniform, and large sized; The size distribution of Fe2 -PAC indicate that it was a high molecular coagulant; The coagulation experiment for treatment of paper wastewater proved that it is a new kind of highly efficient purifying agent.