In this paper, within the frame of Green's function theory, we study the magnetic and thermodynamic properties of the mixed-spin antiferromagnet Y2BaNiO5 in the spin-1 one-dimensional anisotropic Heisenberg model. We find the correlation function, low-lying excitation, ground-state energy, specific heat and static susceptibility of Y2BaNiO5 for different values of exchange anisotropic parameter γ, and the results are in good agreement with experimental and numerical results.