The structural stability, thermodynamic and optical properties of delafossite CuAlO_2 were investigated using the norm-conserving pseudopotential technique based on the fi rst-principle density-functional theory. The ground-state properties obtained by minimizing the total energy were in favorable agreement with previous works. By using the quasi-harmonic Debye model, the thermodynamic properties including the Debye temperature Q_D, heat capacity C_V, thermal expansion coeffi cient a, and Grüneisen parameter g were successfully obtained in the temperature range from 0 to 1 000 K and pressure range from 0 to 80 GPa, respectively. The optical properties including dielectric function e(v), absorption coeffi cient a(v), refl ectivity coeffi cient R(v), and refractive index n(v) were also calculated and analyzed.