Most nuclear island built its foundation on the bed rock. Generally the bearing capacity of these bed rocks is very high and the settlements of these buildings are very small. But in some cases we should consider the nonlinear part of the bed rock deformation when the bedrock is sandstone, Siltstone and Shale ect. under the foundation. Because these Metamorphic deformations are mostly creep deformation. This article analyzed settlements of a nuclear island’s foundation which are much greater than it were being designed. The deformation of sandstone is very large when with high load on top of it. Long time of deformation can bring many problems in nuclear power plant, such as pipe tolerance, building connection problem, cable connection problem and can make damage of them. Compared observed dates and a calculation result by using FEM software. And here gives a simple calculation method on nuclear island foundation settlement on sandstone.