To investigate the effect of organic-modified zinc oxide on the direct current (DC) dielectric properties of polypropylene (PP), zinc salt of 3-(dodecylcarbamoyl)bicyclo[2.2.1]hept-5-ene-2-carboxylate was designed and synthesized in this study. Various concentrations of polypropylene/ zinc salt of 3-(dodecylcarbamoyl)bicyclo[2.2.1]hept-5-ene-2-carboxylate samples were prepared by melt blending modification. The phase structure and melt crystallization characteristics of the blend were studied through scanning electron microscopy and differential scanning calorimetry. The DC conductivity and space charge characteristics of the sampes were tested and compared with the performance of the polypropylene/nano zinc oxide samples. The results indicate that the organic modified zinc oxide generated by the thermal decomposition of zinc salt of 3-(dodecylcarbamoyl)bicyclo[2.2.1]hept-5-ene-2-carboxylate is uniformly dispersed in polypropylene. When the amount of zinc salt of 3-(dodecylcarbamoyl)bicyclo[2.2.1]hept-5-ene-2-carboxylate added is between 0.4 phr and 1.0 phr, the crystallinity of polypropylene is improved. When the addition amount ranges from 0.05 phr to 0.8 phr, zinc salt of 3-(dodecylcarbamoyl)bicyclo[2.2.1]hept-5-ene-2-carboxylate significantly inhibits current density by changing the crystal structure and compatibility of PP, and has an inhibitory effect on space charge after a short circuit of 6 s. Among them, the space charge density of PP/0.05 phr zinc salt of 3-(dodecylcarbamoyl)bicyclo[2.2.1]hept-5-ene-2-carboxylate is about 1.2 C/m3, and the effect of inhibiting space charge is significant, indicating that the organic modified zinc oxide has a certain improvement on the DC dielectric properties of polypropylene.