Abstract: In order to effectively detect permanent scatterers(PSs) in time serial differential radar interferometry,a method,named amplitude information dual-threshold approach(AIDTA),was proposed based on the characteristics of strong reflection and stable backscattering of PS to radar waves.With this method,those points with strong reflection are firstly selected as permanent scatterer candidates(PSCs),and then PSs are taken out from the PSCs with stable backscattering.The proposed method has been proved effective and reliable by an experiment with 26 ERS-1/2 C-band synthetic aperture radar(SAR) images of Shanghai.