In sterolithgraphy rapid prototyping, the support can constraint the parts deformation, and avoid a lot of problems such as collapse, shift and imbalance of the parts. It is of great importance in improving the overall efficiency of rapid prototyping technics software through enhancing the support generation efficiency. Based on this, this paper proposes a discrete-marking support algorithm for treatment of processing on manufactured part model of all Triangle-based discrete-marking on the support plane. The new mesh discrete-marking and automatic support generation algorithm has been successfully applied to the Sterolithography apparatus (SLA). Practical application indicates that the new support generation algorithm improve considerably the support technics efficiency.