A water-soluble polysiloxane (PE-PUVSi) bearing functional benzophenone derivative and hydrophilic polyether side groups was successfully synthesized by hydrosilylation of polyhydromethylsiloxane (PHMS) with 2-hydroxy-4-($eta$-allyloxy-$gamma$-hydroxy)propyloxy benzophenone (MUV-O) and allyl polyoxyethylenepolyoxypropylene ether (F6). The chemical structure, film morphology, and performance of the synthesized polysiloxane were investigated and characterized by spectral analysis, atomic force microscope (AFM), Kawabata evaluation system (KES), and other instruments. Experiment results indicate that PE-PUVSi had an intensive UV-absorbing capacity at wavelengths of 243.6, 289.2, and 325.0 nm. It formed a hydrophilic polysiloxane film on both the fiber and the silicon wafer surface. On the wafer surface, PE-PUVSi actually showed non-homogeneous and phase-separated microscopic film morphology. In addition, PE-PUVSi could provide a bulky softness, good wettability, and antistatic property for the treated fabric and make the treated cotton fabric show a low UV transmittance at the wavelengths between 270 and 330 nm.