Fibrous cellulose and maleated polyethylene (FC-MPE) composites were prepared under melt mixing by maleation of polyethylene {PE) to obtain malefic anhydride (MA) grafted PE (MPE) and successive compounding of the resultant MPE with fibrous cellulose (FC). When increasing the content of added MA to 2 wt %, the grafting efficiency of MA decreases gradually to 84% and the grafted MA chains become longer. Scanning electron microscopy (SEM) reveals strong adhesion of MPE to FC in the FC-MPE composite, which is probably due to the increased compatibility between MPE and FC, in contrast to no adhesion of unmaleated PE (UPE) to FC in the FC-UPE composite. This difference in interfacial structure between the FC-MPE and FC-UPE composites results in quite different mechanical properties for them. With an increase in the FC content to 0 wt %, the tensile strength of the FC-MPE composite increases significantly and reaches 125 % that of pure PE. Furthermore, the larger Young's modulus, larger bending elastic modulus, and smaller elongation of the FC-MPE composite strongly indicate effective transfer of the high tensile strength and elasticity of FC to the MPE matrix through the strong adhesion between FC and MPE.