To improve the performances of waste rubber powder filled polypropylene (PP/WRP) blends, WRP was modified by gamma-aminopropyltriethoxysilane (APTES) via mechano-chemical method, and then maleic anhydride (MAH) grafted PP (mPP) and MAH grafted ethylene-alpha-octene copolymer (mEOC) were chosen as the interfacial compatibilizers. The PP/WRP blends were prepared by melt-compounding and compression, and their morphological structures, tensile properties and thermal behavior were investigated carefully. Results showed that modification of APTES decreased the surface energy of WRP and facilitated its compatibility to PP. Both mPP and mEOC could further enhance their interfacial bonding and mPP was superior to mEOC in increasing the tensile strength and elastic modulus. Thermal analysis revealed relative lower melting temperature and crystallinity but higher activation energy for PLA/WRP blends in comparison to pristine PP.