In this paper, ethylene propylene diene monomer (EPDM) was selected as matrix, and the effects of the ratio of piperazine pyrophosphate (PAPP)/melamine polyphosphate (MPP) on the curing characteristics, filler dispersion, physical and mechanical properties and combustion behavior of EPDM-based composites were investigated. It is found that when the total amount of PAPP and MPP is 40 phr, with the increase of PAPP ratio, the crosslinking density of EPDM compound decreases gradually and the reversion is intensified. Compared with the blank sample, the addition of PAPP and MPP is beneficial to improve the hardness, tensile strength and elongation at break of EPDM vulcanizate, but it would advance the thermal decomposition of EPDM. However, for the blending system, with the increase of PAPP blending ratio, the hardness, tear strength, tensile strength and 100 % elongation stress decrease continuously, and the thermal decomposition process and combustion process have obvious effect on promoting char formation. Compared with the blank sample, the addition of PAPP and MPP is beneficial to prolong the ignition time, reduce the peak heat release rate, and increase the fire performance index (FPI) and limiting oxygen index (LOI). Especially, when the dosage ratio of PAPP/MPP is 20:20, the peak heat release rate of EPDM vulcanizate is reduced by 40.9% compared with the blank sample, the total heat release is reduced by 9.4 %, and the total smoke release is the lowest.