Abstract: A chemical modification was conducted for particleboard flour (PBF)by using alkali (NaOH) and perhydrol (H2O2) or isocyanic acid (IPDI), and then the polylactic acid (PLA)/PBF composites were prepared by melt extrusion. The effects of chemical modification and PBF content on the mechanical properties of the composites were investigated extensively. The results indicated that the interfacial compatibility between the PLA matrix and PBF was improved after PBF was chemically treated with a mixture of NaOH with H2O2 or IPDI, therefore leading to an improvement in the mechanical properties of the composites. The flexural strength and tensile strength increased by 21.63 % and 19.53 %, respectively, for the composites containing 20 wt% of PBF. Based on the results in this work, the composites could achieve the optimum mechanical properties when 20 wt% of PBF treated with a mixture of NaOH with H2O2was incorporated.