Abstract: This paper reported an investigation on the effect of polyvinyl butyral (PVB) as a nonreactive interfacial modifier on the interfacial adhesion and mechanical properties of wood-plastic composites based on poly (butyleneadipate-co-terephthalate) (PBAT) and bamboo powders. It is understandable that the hydroxyl and acetal groups of PVB can interact with the polar groups of bamboo powders and polyester matrix, respectively, makes PVB a capability of interfacial modification. The results indicated that the interfacial adhesion between the bamboo powders and PBAT matrix was improved significantly. There is no significant influence on the mechanical properties of composites from the addition mode of PVB. The tensile strength of the composite was improved from 5.16 MPa to 6.02 MPa at a bamboo-powder content of 30 wt% when 1 wt% PVB in bamboo powders was incorporated.