Abstract: Modification treatment of balsa wood was conducted through 2 wood modifiers of phenolformaldehyde resin and chitosan, and compared the characteristics of the treated and untreated wood with Xray diffractometer (XRD), and Fourier transform infrared （FTIR） spectrophotometer. Results indicated that the ASE and MEE reached around 30%, and the surface hardness and compressive strength parallel grain of the treated wood increased by about 29.7%, 25.0% and 50.0% after PF impregnation, respectively. The chitosan had the better effect of modification than PF because the chitosan had the 4-8 times increments on physical properties of wood than PF. The FTIR and XRD spectra test showed that there was crosslinking reaction between the modifier and the internal parts of the wood. And the modifier could increase the width of crystal region about 0.2 nm, and the relative crystallinity of balsa wood was increased by 4.0% after PF treatment. Moreover, chitosan had an obvious effect on the relative crystallinity of balsa wood, increasing it about 12.2%.