Mechanical properties of recycled PP/rubber/filler systems were studied and mechanisms were discussed on the basis of molar mass and molar mass distribution, morphologies, and thermal behavior. Characteristics of recycled PP/rubber/filler depend on degradation of PP and additional components. Recycling processes decreased impact strength, but it seemed not to affect tensile properties significantly. Aging with UV and moisture affected mechanical properties by some degree of PP chain scissions and ethylene chain crosslinking in EP rubber. Inorganic filler acted as a crack center and accelerated aging degradation. Paint decreased mechanical properties significantly by introducing stress concentrations. Recycle processing decreased the molar mass and increased the molar mass distribution of PP. Aging with UV decreased crystallization temperature and increased crystallization halftime by decreasing nucleation.