采用基于密度泛函理论的第一性原理赝势平面波方法，对Co掺杂CrSi2的几何结构、电子结构和光学性质进行了计算与分析。结果表明，掺杂后的CrSi2 晶格常数无明显变化，禁带宽度增大。由于Co元素3d电子的影响，在费米能级附近出现了杂质能级。掺杂后的CrSi2复介电函数虚部在低能方向发生红移，在 小于1.20 eV，大于2.41 eV的能量范围内光跃迁强度增强。吸收系数的主峰向高能方向移动，峰值增大，在小于1.38 eV，大于3.30 eV的能量范围改善了 CrSi2对红外光子的吸收。光电导率的主峰向高能方向移动，在小于1.16 eV，大于2.36 eV的能量范围内光电导率增强，说明掺杂Co元素后改善了CrSi2特别是 红外光区的光电性质，计算结果为CrSi2光电器件的研究制造提供了理论依据。

The geometry, electronic structure and optical properties of Co doped CrSi2 were calculated and analyzed by the first principle pseudopotential plane wave method based on density functional theory. The results show that the crystal constants of Co doped CrSi2 have no obvious change and its band gap width increases. The impurity level appears near the Fermi level due to the influence of the 3d electrons of Co element. The imaginary part of complex dielectric function of the Co doped CrSi2 is observed a red shift in the low energy direction, and the intensity of optical transition increases in the energy range of less than 1.20 eV and more than 2.41 eV. The main peak of the absorption coefficient moves to the high energy direction, and the peak value increases, which improves the absorption of infrared photons of CrSi2 in the energy range of less than 1.38 eV and more than 3.30 eV. The main peak of photoconductivity moves in the high energy direction, and the photoconductivity increases in the energy range of less than 1.16 eV and more than 2.36 eV, which indicates that the doping of Co improves the photoelectric properties of CrSi2, especially in the infrared region. The calculation results provide a theoretical basis for the research and preparation of CrSi2 photoelectric device.