Nanometer titania has been prepared by hydrolysis of titanium(Ⅳ) sulfate(Ti(SO4)2), and the product was characterized by XRD, SEM and BET. Effects of synthesis methods, titanium(Ⅳ) sulfate concentration, hydrolysis temperature, desiccation temperature, addition of dispersant PVA and strring on adsorption behavior of TiO2 were investigated，and the optimum TiO2 synthesized condition was obtained. In addition, influences of pH value of As(Ⅴ)solution, adsorption kinetics and initial As(Ⅴ)concentration on arsenate adsorption by TiO2 were studied. Results suggested that adsorption capacity of As(Ⅴ) by TiO2 approached 89.28mg•g-1 at the condition of 80℃hydrolysis temperature, 100℃desiccation temperature, 0.2mol/L titanium(Ⅳ) sulfate concentration, pH 6.0 and 100mg•L -1As(Ⅴ)initial concentration. It was found that anatase nanometer tatania was formed by XRD, the mean particle size of nanocrystalline TiO2 was less than 20nm by SEM, and the specific surface area was 167 m2/g by BET.