Sawdust filler taken from White Cham (a type of wood) were mixed with unsaturated polyester (UPE) at 20, 30 and 40% volume fractions. the mechanical and physical properties of the composites treated by NaOH alkali at 0.5, 1, 1.5 and 2% (W/V) along the effect of volume fractions were investigated .The results showed improving in properties comparing with untreated sawdust filler, while heat/alkali treatment at 2%NaOH at different temperature 40, 60, 80 and 100 ˚C also showed improving in properties .the optimal mechanical properties had been obtained at 1% NaOH, and detracted at 2% NaOH. Yet, the mechanical properties at 2% NaOH were improved when heat treated. The optimal mechanical properties were obtained at 80 ˚C. It is worth mentioning that the optimization process was based on the tensile test. Also the thermal conductivity results show better insulation after the treatments especially at 100 oC.