Phenol formaldehyde (PF) and urea formaldehyde (UF) were used to prepare wood-adhesive bonds, respectively. The reduced elastic modulus (E-r) and hardness (H) of the control wood cell wall, the adhesive, and the cell wall penetrated with an adhesive (CW-adhesive) at the wood-adhesive bondline were measured within a certain temperature range from 20 to 160 degrees C using high-temperature nanoindentation (NI). The results indicated that the wood-PF bondline showed a strong dependence on elevated temperatures, while the wood-UF bondline presented better mechanical stability. A reduction of carbohydrates and increment of lignin in wood resulting from heat treatment at a temperature above 140 degrees C were beneficial to increase the micromechanics of wood cell walls at the bondline. Furthermore, the possible post cross-linking reactions between the wood cell walls and PF adhesive molecules during the long heating period at high temperature made a major contribution to a significant increase in E-r and H of the bondline. However, the significant difference in the mechanics of the PF adhesive and CW-PF in bondline after heat treatment negatively affects the interfacial adhesion properties of wood panels.