Abstract: In order to evaluate the probability of bamboo residue as fillers to reinforce high density polyethylene (HDPE), the mechanical and thermal properties of the composites reinforced with 50% bamboo powder, bamboo residue, bamboo pulp fiber, the mixture of bamboo residue and bamboo pulp fiber were investigated, respectively. The results indicated that the tensile strength and modulus of composites reinforced by bamboo residue increased by 45.94% and 114.09%, while the flexural strength and modulus decreased by 8.08% and 17.64%, respectively, compared with that of composite reinforced by bamboo powder. The thermal stability of the bamboo residue/ HDPE composites was suerior to the composites reinforced by bamboo powder, the initial decomposition temperature and the peak relaxation transition temperature of composites reinforced by bamboo residue improved by 21.23 and 10.44 ℃, respectively. From the above, the bamboo residue/ HDPE composites show better mechanical and thermal properties and could be a preferable substitute of bamboo powder/ HDPE composites.