A novel polysiloxane (PSA-PFMS) fabric finishing agent, bearing pendant stearyl acrylate, polyether, epoxy and trifluoropropyl side groups, etc., was synthesized by hydrosilylation of polytrifluoropropylhydromethylsiloxane (PFHMS), stearyl acrylate (SA), allylpolyoxyethylene ether (PEO) and allylglyeidyl ether (AGE). The chemical structure of PSA-PFMS was characterized by infrared spectrum (IR) and proton nuclear magnetic resonance (1H NMR). Film morphology and molecular orientation of PSA-PFMS on silicon wafer substrate surface were observed by atomic force microscope (AFM). Results show that PSA-PFMS can form an inhomogeneous and hydrophobic polysiloxane film with rough, scraggly and microscopic phase separation structures. All of these suggest that the molecular orientation of PSA-PFMS is in such a manner that the stearyl acrylate groups, trifluoropropyl and silicon methyl groups project outward into air, while polyether and Si-O dipole bonds point to the silicon wafer substrate surface. Owing to this highly rough and microscopic phase-separated hydrophobic film and its tight link with fabric, the treated fabrics are altered from hydrophile to hydrophobe with water contact angle of 129.2° and possess favorable washing endurance with WCA of 106.7° after 20 times of standard soaping procedure.