Piezoelectric elastomers were prepared from suspensions of bariumtitanate (BaTiO3) particles in a telechelic polydimethylsiloxane (t-PDMS) by crosslinking the t-PDMS under an electric field. Crosslinking reaction was monitored by measurement of complex dielectric constant epsilon' - i epsilon". Dielectric constant epsilon' increased with increasing BaTiO3 content, and agreed approximately with the theoretical epsilon' calculated with the Maxwell-Wagner theory. Piezoelectric constant d(33) of the poled elastomers was measured by application of compressions in the direction of the poling field. It was found that d(33) was of the order of 10(-11) C/N and increased steeply with increasing content of BaTiO3 but became almost independent of composition in the range of BaTiO3 content from 3 to 14 vol %. To examine the effect of electric field on the aggregation structure of the particles, we observed light scattering of the suspension under an electric field, and found that the scattering pattern became anisotropic. This indicated that the particles are connected like a pearl necklace and ape stretched in the direction of the poling field. The dependence of d(33) on the volume fraction of BaTiO3 was explained by a model. proposed by Banno.