The colloidal silica particles were first modified with methyltriethoxylsilane and methacryloxypropyltrimethoxysilane, respectively, then embedded into acrylic based polyurethane using blending method or in situ method. The effects of the silane couple agent type, modified silica content and preparation method on the redispersibility of silica particles and mechanical properties of polyurethane coats were investigated using 29Si NMR, TGA, FT-IR, particle size analyzer, SEM, DMA and Instron machine. It was found that different silane couple agent and preparation method had obvious influences on the redispersibility and mechanical properties. © 2006 Elsevier B.V. All rights reserved.