The aim of this study was to investigate elasto-plastic thermal stresses in a thermoplastic of Thick Spherical vessels under high pressure The present study deals with spherical shells analysis, The elastic and plastic theory of spherical shell is consider in this search, with a thick sphere subjected to different types of loading such as internal pressure, external pressure and thermal loading have been studies. The Tresca yield condition used in this study. When the applied pressure exceeds the minimum pressure required to initiate the yielding at the inner radius, plastic zone starts to be formed. The residual stress components also were calculated using elastic and elasto-plastic solution result