Bamboo's long-acting mold resistance is essential to its durability and applications. Cinnamaldehyde can be used to protect bamboo against microorganisms, but bonding linkages are easily broken, resulting in poor anti-mold performance. In this study, for the first time, cinnamaldehyde was successfully introduced into bamboo constituents via an in-situ Mannich reaction. As a result of the modification, stronger anti-mold resistance was observed for bamboo with a cinnamaldehyde Schiff base structure. The increased surface hydrophobicity of modified bamboo caused by various levels of cinnamaldehyde fixation effectively negated mold affection. Multiple approaches were used to identify bamboo lignin and xylan as cinnamaldehyde binding sites, revealing the underlying mechanisms of reaction. This study provides new insight into green chemistry-based strategies for bamboo preservation under Mannich reactions, in addition to demonstrating a reliable pathway to improve the mold resistance of bamboo. [Display omitted] • A novel approach to improving bamboo's mold resistance was developed. • Lignin and hemicellulose were identified as the targeted biopolymers. • The mechanisms behind bamboo's linkages and changes in morphology were shown. [ABSTRACT FROM AUTHOR]