X射线衍射和倒易点阵概念抽象，是学习的难点，X射线衍射分析的理论基础是倒易点阵，倒易点阵构建的基础是X射线衍射，两者互为基础. 然而，大部分教科书中X射线衍射和倒易点阵都是分开讲解，更是给学习理解带来了困难，本文系统介绍了X射线衍射原理，并基于X射线衍射引出倒易点阵，将X射线衍射和倒易点阵统一讲解，使学习理解更加容易.

The abstract concepts of X-ray diffraction and reciprocal lattice are difficult to learn.The theoretical basis of X-ray diffraction analysis is reciprocal lattice，and the construction of reciprocal lattice is based on X-ray diffraction.The two concepts are based on each other.However，X-ray diffraction and reciprocal lattice are explained separately in most textbooks，which brings difficulties for learning and understanding.In this paper，the principle of X-ray diffraction is introduced systematically.Then the reciprocal lattice based on X-ray diffraction，X-ray diffraction and reciprocal lattice are explained in a unified way in order to make learning and understanding easier.