晶体的宏观对称性影响着其物理性质，其中介电常数作为重要的物理量，可通过理论计算有效简化实验测量.本文基于晶体介电常数的二阶张量形式，提出了一种旋转坐标轴的方法，旨在更直观地求解晶体的介电常数.本文以正四面晶体结构为例，在新坐标系中对晶体进行对称操作，求得旋转矩阵，进而实现晶体介电常数的简化，该方法显著改善了现存方法的经验性和抽象性.推导过程不仅直观地呈现了晶体介电常数的退化，还能够加深同学们对介电常数物理本质理解和计算能力强化.

Crystals exhibit higher structural symmetry, which influences the macroscopic physical properties of crystals. As an important physical quantity, dielectric constant can be effectively simplified through theoretical calculations. Furthermore, theoretical calculations can simplify experimental measurements. In this work, a method of rotating coordinate system is proposed, basing on the dielectric constant of crystals as a secondorder tensor. To be more intuitive, the dielectric constant of the crystal can be calculated. Taking the regular tetrahedral crystal structure as an example, the symmetry operations on the crystal in the new coordinate system can achieve rotation matrix. Consequently, the degradation of the dielectric tensor is achieved. Compared with the existing methods, this approach substantially mitigates the empirical limitations and mathematical abstraction. The whole derivation visually demonstrates the degradation of the crystal dielectric constant, while simultaneously deepening students comprehension of the physical properties of the dielectric constant and advancing their theoretical calculation ability.