We have used molecular dynamics method with quantum corrected Sutton-Chen type many-body potentials to study the structure and thermal stability of［110］ Au nanowires, and investigate its melting mechanism and shape evolution by introducing the Lindemann index and the minimum radius. The results show that the transformation from fcc to hcp structure occurs in local regions of nanowire before premelting. The melting starts from surface and evolves into interior region, resulting in the overall melting of the nanowire. Subsequently, the neck occurs and induces the final breaking of nanowire into a spherical cluster.