Introduction: Magnetoelectric (ME) materials become magnetized when placed in an electric field and electrically polarized when placed in a magnetic field. Thus an effective conversion between electric and magnetic energy becomes possible, and ME materials present themselves as one kind of smart materials. They can be classified into two classes: single phase and composite. For single phase materials, due to the primary requirement to observe the ME effect is the coexistence of magnetic and electric dipoles in an asymmetric structure, the number of compounds that exhibit ME effect is limited, the ME coefficient, α E = (∂E/∂H) T , is small, working temperature is low and involved expensive materials and processing techniques. These limitations can be overcome when shifted to composites, which usually consist of magnetostrictive and piezoelectric phases, resulting in a ME effect as product property of this combination [1]. Experimental: Samples were synthesized using wet chemical method. CoFe 2 O 4 powder obtained from appropriate solution by coprecipitation was introduced as core to the solution of acetic acid, barium hydroxide and titanium(IV) n-Butoxide which is then gelated on the surface of the CoFe 2 O 4 core during heating and stirring. The gels were dried, presintered and pressed into pellets followed by a heat treatment and electrically poling procedure, then painted by silver paste for electric contacts. Crystalline structures of the composites were investigated by X-ray diffractometer (XRD). Magnetic properties were studied using a pulse field magnetometer. Magnetostriction was measured using strain gauge method. AC susceptibility and ME coefficient were investigated using lockin technique in which AC fields with frequencies from 1Hz to 4kHz and amplitudes from 0,1Oe to 20Oe superimposed onto a DC magnetic field up to 6500 Oe were employed. Input resistance and capacitance of the lock-in are 100MΩ and 25pF. All measurements were carried out at room temperature and ambient pressure. Discussions: The XRD patterns suggested that the composites consist two single phases: CoFe 2 O 4 and BaTiO 3 . The saturation magnetization and coercivity of the CoFe 2 O 4 component in the composite are 78emu/g and 460Oe, which are similar to those of the bulk sample. ME coefficient α E was determined using the equation α E =V/(d.H AC ) where V is output voltage of the lock-in, d is the thickness of the sample and H AC is the amplitude of the AC field. ME coefficient-Bias field curves, α E -H DC , has a hysteretic nature, and a remanence is also observed. Under an AC field of 10Oe with frequency of 270Hz, the maximum longitudinal and transversal α E are 1,58mV/Oe.cm and 0,95mV/Oe.cm, see Fig.1. These α E are about 20 times higher as compared to those of the reference sample which is produced by mixing the two powders, suggesting that the coupling between the two phases in the core-shell structure is much better than those in the mixture. In the mixed structure, the longitudinal ME coefficient is smaller than the transversal ...