Abstract: Mimicking the st ructure of nacre , the poly(t ripropylene glycol diacrylate , TPGDA) / SiO₂ nanocompositethin film was prepared using an evaporation-induced self -assembly procedure on the quartz glass subst rate. Thest ructure of the nanocomposite thin film was characterized by means of FT- IR spect roscope , X- ray diff raction(XRD) and t ransmission elect ron microscope ( TEM) . The f rictional force behavior of the nanocomposite thin filmwas tested. The formation mechanism of the poly ( TPGDA) / SiO₂ nanocomposite thin film was investigated. The results indicate that the thin film is composed of organic and inorganic layers in alternately orderly arrangement . Thedistance between the organic layer and inorganic layer is 2. 69 nm before polymerization and 2. 35 nm af ter polymerization. Moreover , the polymerized film has preferable antiwear property.