Abstract: The density functional method with relativistic effective core potentials (RECP) and LANL2DZ basis set are used to investigate the possible stable geometrical configurations and relative stabilities of the lowest-lying isomers of Y-doped gold clusters, Au_nY (n = 1-5). The results indicate that the ground-state structures of AuY, Au₂Y and Au₃Y clusters are planar form, and they are 3D form for Au₄Y and Au₅Y clusters. The stability trend for the ground-state structures of Au_nY (n = 1-5) clusters is analyzed in terms of the atomic averaged binding energy (E_b), the second-order difference in energy (Δ²E), the fragmentation energy (ΔE) and the energy gap (E_g) between the HOMO and LUMO. The results show that Au₃Y cluster is magic cluster with high chemical stability.