The fixation mechanism of CuAz preservatives in bamboo was studied with bamboo as the experimental material in the present paper. The purpose of the study is to understand the interaction between preservatives and bamboo, provide a theoretical basis for the design and optimization of preservatives formula and for improving preservative treatment. The chemical combination between preservatives and bamboo components was analysed by ATR Fourier transform infrared spectroscopy (ATR-FTIR), and the results show that the infrared spectra of lignin after treatment changed significantly. The lignin characteristic peaks (1 510 cm^-1 ) changed obviously. Lignin phenolic hydroxyl was involved in the lignin-copper complex formation. Holocellulose＇ s spectra after treatment changed little, with just a change in hemicellulose carboxyl and hemicellulose acyl-oxygen bond (C-O) stretching vibration.