In this study spruce wood (Picea excelsa) was acetylated and subjected to a variety of artificial weathering conditions (water only, light only, water and light together) for 300 h, then the wood surface was analyzed for chemical changes using Fourier Transform Infrared (FTIR) spectroscopy and for structural changes using Scanning Electron Microscopy (SEM).The results shown that weathering process affected the functional groups on the wood surface. Light and water, both acting together (full weathering) have caused the greatest damage to the surface polymer structure and greatest chemical and physical changes. Changes observed in the infrared spectra of the surfaces after wood samples were subjected to water- only weathering are minor compared with the effect of light-only and water plus light. It causes changes in physical structure and minor effect-is on wood chemical structure. The greatest changes were related to the functional groups aromatic structure of lignin.The SEM data show that physical changes due to the accelerated weathering including light and water for 300h in acetylated wood surface are much lower than those in the untreated wood surface. SEM pictures and FTIR show that acetylation of the wood to protect the surface from the damages caused by the weathering agents of light and water.