1-3 polymer-based piezoelectric composites were fabricated using epoxy as matrix by the cut-filling method. The influences of shape parameter on properties of the piezoelectric composite, which include the unit cross-sectional area and the aspect ratio w/t were analyzed. The results indicate that with the increasing of the unit cross-sectional area, the quality factor value Qm increases and the hydrostatic piezoelectric voltage gh increases and then goes down rapidly while the PMN volume fraction φ(PMN) is kept under the 50%. When the φ(PMN) is 60%, gh is decreased. The trend of the hydrostatic figures of merit dh·gh is similar with gh as the change of the unit cross-sectional area, but the value is different. In the 60% PMN volume fraction, the optimal value of the dh·gh is chosen. With the increasing of the w/t, the hydrostatic pressure sensitivity Mh, the dh·gh values and the Qm values are all decreased rapidly, and the thickness electromechanical coupling factor kt is increased. In other words, the test results show that the smaller of unit cross-sectional area and thinner of thickness, the more helpful for frequency bandwidth and sensitivity when it is used in transducer.