In this study, oil palm trunk core-lumber (OPTCL) producing from oil palm based plywood industries waste materials was studied using microwave drying technique for material optimization. Microwave dried oil palm trunk core part was impregnated with phenol formaldehyde resin as a matrix by using high-pressure vacuum impregnation chamber. Microwave drying optimized the drying conditions, avoided burning, shrinkage and increased the permeability of oil palm trunk (OPT). OPTCL impregnated in different times and compared with kiln dried OPTCL and rubber wood (RW). Impregnation of microwave dried core part of oil palm trunk was carried out first time. The microwave dried impregnated OPTCL exhibited higher mechanical properties as compared to microwave dried OPT. Results indicated that OPTCL impregnated for 60 min shows lower mechanical properties as compared to RW. The morphology of resin loaded oil palm trunk core cell wall or lumen ultra structure was analyzed by scanning electron microscope (SEM) and it clearly showed full penetration of resin into OPTCL cell. The mechanical properties of impregnated samples were analyzed according to BS and ASTM standards.