Micro-indentation is widely used in evaluating the mechanical properties of ceramics. It is also an important measure in the study of machinability of brittle materials. Because of the complexity of interaction in the vicinity of the contact zone between the indenter and work material, an analytical or experimental method is unable to predict the detailed evolution process of deformation. With the aid of the finite element method, this paper analyses the behaviour of a silicon subjected to micro-indentation by a spherical indenter. The development of stress fields was thoroughly simulated. A constitutive relationship was confirmed based on a comparison with experimental observations. This study offers essential information for the indentation of ceramics and a deeper understanding of material removal mechanisms in machining brittle materials.