This paper investigates the pyroelectric of poled antiferroelectric (AFE) ceramic Pbo.97Lao.02 (Zro.69Sno.196 Ti0.114)03 and its remnant polarization dependence of hydrostatic pressure. The results show that the bound charges of poled sample can be released in short time by temperature field or pressure field. The released charge abruptly forms a large pulse current. The phenomena of released charge under external fields result in the ferroelectric-AFE phase transition induced by temperature or hydrostatic pressure.