A piezoelectric ceramic/rubber composite comprising linearly aligned Lead Zirconate Titanate (PZT) particles as pillars in a silicon rubber matrix was fabricated. The optimum fabrication conditions of pseudo 1–3 composites (referred to as “aligned-type” composites) were evaluated as the functions of the electric field strength and the piezoelectric particle size. The piezoelectric strain constant d33, which represents the value of the electric charge per unit force generated from a piezoelectric material, and the ratio of the number of particles involved in the alignments (RPIA) to all particles in an RPIA sample were used to quantitatively evaluate the composites. The d33 exhibited linear dependence on the piezoelectric particle size and a non-linear dependence on the RPIA. The RPIA depended on both the electric field strength and particle size. The electric field strength dependency of the RPIA exhibited a maximum at approximately 2 kV/mm. The optimum condition for the fabrication of the aligned-type piezoelectric rubber composite was achieved an electric field strength of 2.0 kV/mm with larger PZT particles.