从理论上探讨了高Tc超导体的动态热膨胀反常行为对正常态和超导态分别用两组参数拟合实验数据，结果基本吻合与正常态相比，超导态的非谐性增强，原子间相互排斥的不对称性和声子的软化现象均增强，尤其是声子的软化更为显著此结果有助于理解高Tc超导电性机理 The dynamic thermal expansion abnormalities of high-Tc superconductors were discussed in theory. Two sets of parameters were used to fit the normal and superconducting states, respectively. The results were basically consistent. Compared with the normal state, the anharmonicity of the superconducting state was enhanced, Mutual exclusion asymmetry and phonon softening are enhanced, especially the phonon softening is more pronounced This result helps to understand the high Tc superconductivity mechanism