Waterlogged wooden cultural relics have been constantly excavated and preserved, driven by increasing public interest and upgrading archaeological technologies. Wood cells' morphology and chemical structure from waterlogged wooden relics normally undergo non-uniform degradation or changes, presenting a different “new material” from sound woods. PEG and sugars have been widely applied for consolidation. This study selected teak (Tectona sp.), the main timber species of the “Xiaobaijiao Ⅰ” shipwreck, as the research object. Based on the developed sample preparation method of nonembedded nanoindentation suitable for wooden cultural relics. The PEG, sucralose and trehalose treated samples were evaluated by Nanoindentation technology (NI) and studied by infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The results showed that samples prepared by the nonembedded method could accurately measure the longitudinal elastic modulus and hardness of wood cell wall, and the PEG, sucralose and trehalose were able to significantly improve the elastic modulus of fiber cell wall respectively, by 6.9%, 25.4% and 29.1% compared to untreated samples, and increase its hardness by 9.3%, 25.9% and 13.6%. Infrared spectroscopy showed that PEG, sucralose and trehalose penetrated the wood, and thermogravimetric analysis confirmed that partial consolidants could enter the wood cell wall, which was the main reason for the improvement of cell wall strength. In general, sucralose and trehalose were more suitable than PEG for consolidating the waterlogged archaeological wood, with sucralose being the most effective consolidant in this research. This research provided a proven method for the accurate performance evaluation of consolidates for waterlogged wooden cultural relics such as shipwrecks and could provide a scientific basis for their consolidation and conservation.