Composite coagulants have drawn a widespread attention recently for its superior coagulation-flocculation performance. Fe and Ti based coagulants, as a kind of inorganic metal water treatment agent, h have received huge attention, but there is little study about the preparation and characterization of composite coagulate composite with Ti4+. In this paper we prepared a composite coagulant, in which the Ti (SO4)2 was introduced as coordination complexes, PO3-4 as stabilizer and complexant. Then, the FT-Infra Red spectrum (FT-IR) and ultraviolet/visible absorption spectrum (UV-Vis) were adopted to characterizse the changes of chemical group, species distribution of coagulants in case of varies Ti/Fe, P/Fe and OH/Fe molar ratio. The results shows other than simple mixture of the raw materials, the introduction of Ti4+ and —PO4 group synthesized the chemical group bond as Ti—O, —Fe—P—Fe— and —Ti—P—Ti—, which were beneficial to the degree of polymerization and increased the stability of the product. Furthermore, when the Ti/Fe molar ratio of 1∶8, P/Fe was in the range of 0.2~0.3, the optimal material is suitable for the generation of Fe—P—Ti— chemistry bond and medium polymer as Fe6(OH)6+12, ［Fex(OH)y］2H2PO(6x-2y-1)+4. Whereas, too much addition of Ti4+, PO3-4 and HCO-3 deteriorated the polymer structure, leading to the presentation of precipitate as TiO2, Ti3(PO4)4 and FePO4, which will decrease the coagulation performance.