采用第一性原理赝势平面波方法对应力调制下β-FeSi2的电子结构及光学性质进行了计算，全面分析了应力对β-FeSi2能带结构、电子态密度和光学性质的影响。在各向同性应力的作用下，压缩晶格使β-FeSi2的导带向高能区漂移，带隙变宽，拉伸晶格使导带向低能区漂移，带隙变窄，且当拉伸应力增加到-25 GPa时，费米能级穿过了价带和导带，β-FeSi2由半导体变成了导体；压缩晶格会使各光学参数发生蓝移，增大β-FeSi2的吸收系数和光电导率，降低反射率，而拉伸晶格会导致红移，增大静态介电常数，折射率n0和反射率，降低吸收系数。 施加应力可以调节β-FeSi2的电子结构和光学性质，是改变和控制β-FeSi2的光电传输性能的有效手段。

A detailed theoretical study on the band structure, electronic density and optical properties of β-FeSi2 under the isotropic stress is performed based on the first-principles pseudopotential method. The results show that the lattice constants of β-FeSi2 change with different stress. With the compression stress increasing, the densities of Fe-d and Si-p states decrease, and the conduction bands move to higher energy while the valence bands have little change that makes the energy gap widened; when the lattice is stretched, the densities of Fe-d and Si-p states increase, and the conduction bands move to lower energy while the valence bands have little change which makes the energy gap narrow down. The valence and conduction bands are traversed by the Fermi energy when stretch stress is -25 GPa that means the semiconductor β-FeSi2 converts to the conductor. Compressing lattice will lead to the blue shift, increase the absorption index and photoconductivity, and decrease the reflectivity. While stretching will result in the red shift, increase the static dielectric constant, refractive index n0 and reflectivity, and decrease the absorption index. Applying stress can effectively regulate the electronic structure and optical properties of β-FeSi2, which is an effective way to change and control the photoelectric transmission performance of β-FeSi2.