Ultra-precision raster fly cutting (UPRFC) is a discontinuous fly cutting, whereby the diamond cutting tool flies with spindle rotation and cuts the machined surface discontinuously. Accompanying the motion of spindle with a raster tool path covering the whole machined surface, the diamond tool can cut and form complex surface structures. The cutting mechanism of UPRFC makes it widely utilized in manufacturing non-rotational symmetric structures like pyramid array, free-form surface, F-theta lens, tetrahedron array, micro-lens array etc. The form accuracy of fabricated products could be down to submicron level, and surface roughness down to non-metric level. UPRFC is potentially used to fabricate products in multiple industry fields such as aerospace, automobile, laser, communication, optics. Study of the cutting mechanism of UPRFC and the influences thereof on surface integrity is a key topic since it helps to improve the machined surface quality. The intermittent cutting mechanism of UPRFC is quite different from other ultra-precision machining processes, e.g., single-point diamond turning, micro-milling; correspondingly, it may cause different effects on surface finish. This chapter will talk about the cutting mechanism and surface formation of UPRFC in five parts. Part 1 gives an overview to UPRFC technology and the application thereof on fabrication of optical products. Part 2 delivers a comprehensive knowledge on the material removal mechanism of UPRFC both in theoretical and experimental aspects. Part 3 talks about material sliding during chip formation, and it caused surface microwaves in UPRFC process; in this part, the appearance and influence factors of microwaves will be presented. Finally, tool wear features and their influences on the quality of machined surface were investigated in Part 4, and a short conclusion is summarized in Part 5. This chapter will give reader a comprehensive understanding of the cutting mechanism and surface generation in UPRFC.