PP-g-MAMg was prepared by blending polypropylene grafted maleic anhydride (PP-g-MAH) with magnesium stearate. The dielectric properties, volume resistivity and breakdown field strength of PP-g-MAMg ionomers were characterized by IR and XPS. The results show that with the increase of Mg2+ content, the dielectric constant and dielectric loss of PP-g-MAMg ionomers first increase and then decrease, and the volume resistivity of PP-g-MAMg ionomers first increases and then decreases, the breakdown field strength first decreases, then increases, and then decreases; the rheological properties of PP/PP-g-MAMg ionomer composites were studied by rotating rheometer. The results show that after adding PP-g-MAMg, the storage modulus("G" ^"""" )and loss modulus ("G" ^"""" ) of the system are improved compared with those of pure PP, and the high frequency region is more obvious than the low frequency region; the addition of PP-g-MAMg has a great influence on the composite viscosity of PP. Compared with pure PP, the composite viscosity of the PP/PP-g-MAMg system is higher(η^*) has an obvious upward trend.