To enhance the barrier properties and hydrophobicity of bamboo fiber packaging materials, hemicellulose was green-extracted from moso bamboo using a freeze-thaw hydrothermal method, and subsequently amphiphilic hemicellulose derivatives (OSAHC) were prepared by esterification modification of hemicellulose with octenyl succinic anhydride and applied to the surface coating of bamboo fiber paper. Bamboo fiber modified packaging paper materials with good barrier and water resistance properties were prepared. Systematic investigations of the microstructure, mechanical performance, and barrier properties of the coated papers revealed that the amphiphilic hemicellulose derivatives effectively filled the paper pores, formed strong hydrogen bonding with the fibers, and created a dense hydrophobic surface layer. At a coating dosage of 6%, the tensile strength of the modified paper increased to 20.6 N·m/g; at a coating dosage of 10%, the water vapor transmission rate and oxygen transmission rate were significantly reduced to 114 g/(m2·d) and 472 g/(m2·d), respectively. The post-harvest preservation experiment of cherries demonstrated that the coated paper achieved a preservation effect comparable to that of commercial polyethylene films. This work provides an effective pathway for the high-value utilization of bamboo and the development of high-performance bamboo-based packaging materials to replace plastics.