^aDepartment of Physics and Information Engineering, Huaihua University,

Huaihua 418008, China

^bSchool of Materials Engineering, Yancheng Institute of Technology, Yancheng

224051, China

^cSchool of Physics and Electronic Engineering, Sichuan Normal University,

Chengdu 610066, China

We have studied the structural, elastic anisotropy, electronic properties and optical properties of CdGeP2 crystal by using first-principles method. The effect of pressure on the elastic constants of CdGeP2 was explored. The changes in the anisotropy of the CdGeP2 at different pressures were analyzed in detail by three-dimensional (3D) and 2D projections of bulk modulus and Young's modulus. The electronic properties, including the band structure, density of states, were investigated, and it turned out that CdGeP2 is a semiconductor. Furthermore, we analyze the dielectric function, refractive index, extinction coefficient, absorption coefficient, and electrical conductivity of CdGeP2 in detail. Finally, the influence laws of temperature and pressure on Debye temperature, heat capacity and Grüneisen parameter are obtained, respectively.