The curing characteristics and mechanical properties of natural rubber/polypropylene blends were investigated with the aim of improving tensile strength. Two different types of filler were tested: carbon black and reclaimed rubber. It was found that, the increasing carbon black compositions improve the tensile strength of the NR/PP blends. Reclaimed rubber shows beneficial effect by increasing the scorch time and decreasing the cure time of the NR/ PP blends. And the use of reclaimed rubber results in compositions of improved elasticity and tensile mechanical performance.