Polypropylene (PP) have been modified by natural eucommia rubber (EUG) in this work. The mechanical properties, processing properties and micro-structure of different blends were studied to find the best mixed ratio. The results showed that the impact strength of PP blended with 25% eucommia was improved as much as twice. The survey of DSC indicated that degree of crystallinity (XC) of PP was first promoted and later inhibited with the part of eucommia rubber increasing, when it was 10 % that XC got to the maximum of 30.35%. Polarizing microscopes exhibited that the addition of natural eucommia rubber could promote the spherulite refinement and amorphous area of PP increases significantly. Morphology of fracture surfaces observed by SEM demonstrated that the brittle fracture of pure PP material transformed to the ductile fracture with eucommia rubber and then the toughening mechanisms were discussed.