Dense Pb(Sc0.5Ta0.5)O-3 (PST) ceramics were fabricated by a two-step sintering technique. X-ray diffraction analysis showed that the order of degree is 0.91 and micrograph indicated that the grain size is 1-3 mu m. Under dc bias of 700 V/mm, the detective figure of merit reaches over 70 x 10-5 Pa-1/2, where the pyroelectric coefficient, dielectric constant, and dielectric loss are 650 x 10-8 C center dot(cm2 center dot K)-1, 6600, and 0.019, respectively. Such superior pyroelectric properties and fine grain size give it a particular advantage in application for uncooled focal plane array detectors.