Multiferroic heterostructures CoPd/0.68Pb(Mg1/3Nb2/3)O-3-0.32PbTiO(3) (001) (CoPd/PMN-PT) with the thickness of 10 nm were fabricated via magnetron sputtering. The effect of electric field on remanent magnetization, coercivity, and magnetization reversal have been subsequently investigated. A large electric field modulation of magnetism is obtained in strain-mediated CoPd/PMN-PT multiferroic heterostructures. Not only the remanent magnetization but also the magnetic coercivity of CoPd film can be effectively modulated by an electric field. Up to 30.7% of magnetization difference is observed by electric field at the vicinity of the magnetic coercivity. Taking the advantage of the different coercivity controlled by electric field, the magnetization reversal can be assisted by electric field. The magnetization reversal process of the CoPd/PMN-PT heterostructure is dominated by the Kondorsky model. Our results provide great opportunities for electric field-controlled magnetic devices.