Focused ion beam (FIB) machining is an ideal technique for both micro-and nanofabrication. This chapter describes a deterministic fabrication approach to accurately obtain micro-and nanostructures. It starts with a detailed introduction of FIB machining mechanism, followed by a surface topography simulation method and a divergence compensation method. The effectiveness of this fabrication approach has been fully demonstrated through a number of experiments which show that the surface topography of the machined material can be precisely predicted; the divergence compensation method can reduce the machining error, and the machined surface form accuracy can be dramatically improved. Combining with other techniques, some hybrid manufacturing techniques based on FIB machining are also introduced.