The increasing usage of polymers in automotive industry requires low density and high modulus polymers without losing its tensile strength. Therefore, the main challenge is to replace high density talc-based additives with low density and sustainable filler for density reduction. At this context, wood fiber is remarkable in terms of its low density. The wood fiber filler incorporated into polymer by using ultrahigh speed thermo kinetic mixing method. A series of experiment was performed by using totally 100 grams of sample in different loads (30% or 40%) of organic filler. In addition, 2% compatibilizer was used for comparison. After compounding, test samples were prepared by using mini injection molding and then their mechanical properties as well as thermal properties and homogeneity of the mixture were characterized by UTM, TGA, DSC and SEM. The test results showed that 40% wood fiber addition increased the tensile strength of the PP 4 times more (from 8.6 MPa to 36 MPa) than the talc added PP. Meanwhile the tensile modulus did not undergo a change but managed to kept same as with the talc added PP. Also, density measurements proved that wood fiber addition decreased density by 14%. SEM images revealed that addition of compatibilizer increased the homogeneity and results confirm tensile strength increase. Likewise talc added PP, crystallinity increase with wood fiber addition also proves that wood fiber can replace talc.