反射式高能电子衍射（RHEED）是一种广泛用于晶体结构表征的技术，与X射线衍射相比，RHEED具有更简便的操作流程以及更强的衍射信号.这些优势使得RHEED特别适合用于物理实验教学，有效辅助学生理解晶体结构.尽管如此，RHEED在教学中的普及仍受限于缺乏简单直观的数学模拟方法.本文基于自由电子的平面波模型，提出了一种简单的RHEED衍射理论模型，并将其扩展应用到有限尺寸晶体.通过与实验数据的对比，验证了我们提出的模拟方法的准确性和可靠性，因此有望促进其在物理教育领域的广泛应用.

Reflection High Energy Electron Diffraction (RHEED) is extensively utilized for characterizing crystal structures. Compared to X-ray diffraction, RHEED offers the advantages of simplicity in operation and strong diffraction signals, holding great potential for applications in university physics and solid-state physics education. However, the lack of mature and intuitive simulation methods for RHEED patterns has hindered its broader adoption in educational settings. This article begins with the free-electron plane wave model to discuss the theoretical model of RHEED and extends it to the case of finite-sized crystals, providing detailed mathematical exposition. The results of this model fit well with relevant experiments, demonstrating its effectiveness and promoting the application of RHEED in related teaching fields.