Coagulation behavion of Titanium tetrachloride and polyaluminum chloride was comparatively investigated in terms of the removal of turbidity and natural organic matter with surface water. The growth, breakage and re-growth nature of flocs were also compared, The results show that the removals of chemical oxidation demand and dissolved organic carbon were 51.5% and 74.8% at optimal dosage for and PACI, respectively. The floc breakage and re-growth indicated that and PACI coagulation occurred not only by charge neutralization but also by a form of sweep flocculation. Besides, flocs formed by PACI had better recoverability than the flocs formed by TiCl4. Sludge produced form TiCl4 flocculation was calcined at 600C to produce Tio2, and the photocatalytic activity in removing reactive brilliant red was evaluated in comparison with commercially available Tio2. The photocatalytic oxidation rates of K-2BP after 2 h photocatalytic reaction were 91.4% and 92.9% for as-prepared Tio2 and P-25, respectively.