To gain relatively concentrated chemicals rather than providing liquid fuels, a pyrolysis pretreatment method that running at a broader temperature range than that of torrefaction, had been proposed and named as low-temperature deoxidization. In this study, low-temperature deoxidization of cellulose was performed at various temperatures (200, 230, 260, 290, 320, 350 and 390 degrees C), and then the solid products were used for pyrolysis experiments in the pyrolysis gas chromatography mass spectrometry (Py-GC/MS). The evolution of functional groups during low-temperature deoxidization was analyzed using two-dimensional correlation spectroscopy, which allowed a number of formation mechanisms to be proposed for typical products and demonstrated that the main deoxidization temperature range corresponded to 290-320 degrees C. Notably, low-temperature deoxidization of cellulose was shown to involve the initial breakage of infra- and intermolecular hydrogen bonds, which resulted in the occurrence of ring-opening reactions and afforded straight-chain olefins that were subsequently dehydrated at higher temperatures. Finally, cellulose aromatization reactions were observed starting from similar to 290 degrees C. In summary, the obtained results showed that lower temperature pretreatment (200-290 degrees C) influenced only the content of oxygen-containing components in liquid products obtained by subsequent pyrolysis, whereas higher temperature pretreatment (320-390 degrees C) also influenced the types of components.