In this paper, a framework of surface generation model in the fast tool servo (FTS) machining of optical microstructures will be described. The integrated model is totally composed of a tool path generator (TPG), a surface topography model (STM) and an optimization model (OM). To develop the tool path generator, two parts should be involved. The first part is the tool path generated based on cutting conditions such as the feed rate and spindle speed, the geometry of optical microstructures, and diamond tool geometry. Another part is the synchronized motion generated by the tool actuation of the FTS at a bandwidth higher than the rotational frequency of the spindle. The surface topography model will be generated based on the TPG and used to predict the technological aspects of FTS machining. It takes into the account the kinematic and dynamic characteristics of the cutting process. The former includes the tool path generated by the tool path generator. The later includes the relative vibration between the tool and the workpiece caused by the axial error motion of the spindle as well as the synchronized motion of the FTS system. The optimization model will be undertaken by an iterative algorithm, which will be developed based on the TPG and STM. The OM will be expected to output the verified tool path, the suggested optimum cutting conditions, and the diagrams with predicted cutting performance characteristic and process parameters being investigated. Eventually, the successful development of this surface generation model can contribute for the knowledge of ultra-precision machining with FTS and the further development of the performance of the machining system.