This works investigate the morphology and properties of two kinds of thermalplastic natural rubber (TPNR) blends. One is the blends of Natural Rubber(NR) and isotactic polypropylene(PP) , and another one is the blends of NR grafted with poly(methyl methacrylate)(NR-g-PMMA) and PP. The tensile strength and elongation at break of TPNRs increased with an increase in PP content, and TPNRs of NR-g-PMMA/PP blends had higher tensile strength than NR/PP blends. The morphology of TPNRS examined by scanning electron microscopy disclosed that NR or NR-g-PMMA particles dispersed in PP matrix, and the dispersed phase became smaller with an increase in PP content. Themogravimetry analysis included that NR-g-PMMA/NR blends had better thermostability than NR/PP.