This study aims to apply the organic titanium compounds as light-sensitive material. In this paper we report the behavior of light-sensitive material of alkyltitanates (Ti (OR) ₄, R=alkyl group). Alkyltitanates are hydrolyzed easily even with a trace of moisture in the air, and these hydrolysis products have very strong hydrophobic surface and positive surface potential. On irradiating these hydrolysis products with U.V. ray, its hydrophobic surface changes gradually in to hydrophilic surface and simultaneously its surface potential changes from positive to negative in accordance with increase of irradiation time. These changes occure primarily by the decrease of residual alkyl group. Alkyltitanates have also a property which is colored by irradiating with U.V. ray.