江门中微子实验(JUNO)将建设一个有效质量为2万吨的液体闪烁体(液闪)中心探测器，其首要物理目标是通过精确测量反应堆中微子的能谱来确定中微子质量顺序以及精确测量中微子的振荡参数。中心探测器的能量分辨率要求达到前所未有的3%水平，同时要求探测器处于极低的天然放射性本底环境，这就对探测器的设计提出了很高的要求。在探测器设计阶段，可靠的探测器模拟能对探测器设计的方方面面提供指导性的意见，对探测器屏蔽层厚度、探测器各种材料的洁净度、光电倍增管和液闪关键性能参数提出具体的要求，从而保证探测器性能指标满足各项物理研究的要求。针对中心探测器设计的模拟研究，要求具备精确的事例产生子、构建精细的探测器几何、完善的光学模型、以及顶点重建和能量重建算法，才能得出正确的结论。

JUNO(Jiangmen Underground Neutrino Observatory) experiment was proposed to construct a large liquid scintillator central detector with 20k ton fiducial mass. The primary physical goal of JUNO experiment is to determine the neutrino mass hierarchy(MH) and probe the fundamental properties of the neutrino oscillation. The JUNO central detector is required to be with 3%@1MeV energy resolution and very low radioactivity background, which is a big challenge to the detector design. In order to ensure the detector performance can meet the physics requirements, reliable detector simulation is necessary to provide useful information for detector design, including detector structure, impurity of detector materials, requirements on PMT and liquid scintillator optical parameters. The detector simulation study can only draw right conclusion with the implementation of accurate event generators, detector geometry, optical models, vertex reconstruction, and energy reconstruction algorithms.