Abstract: A localized deformation zone near Muyu town of Qingchuan county was observed on the InSAR interferograms of the great 2008 Wenchuan earthquake. The Muyu deformation zone was about 15 km long and 10 km wide, with line of sight displacement up to dozens of centimeters. Some researchers proposed that the deformation zone is caused by a strong aftershock （M_W6.1） in Qingchuan county on May 25, 2008, and they adopted seismic source parameters very different from seismic inversions. To verify reliability of the seismic source inversions, we use teleseismic body wave and local Rayleigh wave spectra to constrain focal depth and fault plane of the strong aftershock. Thereafter, we compute ground displacement and proposed that the aftershock was not the direct cause of the localized deformation zone. Then we discuss some candidate mechanisms which might explain the localized deformation.