The theoretical frames of MEND are spherical optical model, intra-nuclear cascade model, pre-equilibrium emission theory based on exciton model, evaporation model and Hauser-Feshbach statistical theory with width fluctuation correction. MEND程序的理论框架基于球形光学模型、核子的核内级联发射模型、以激子模型为基础的预平衡发射理论、蒸发模型和带宽度涨落修正的Hauser-Feshbach统计理论。