Abstract: As a high-temperature phase of Pu, δ-Pu doped with little Ga can stay to room temperature. Crystal structure and electronic structure of systems with different contents of Ga are calculated with density functional theory (DFT) method. Calculations mainly include lattice constant, density, formation energy, density of states(DOS), electron density and Mulliken population. It shows that within studied doping scope, lattice constant of systems decrease and density of systems increase with increase of content of Ga, while stability of system with 6.25% content of Ga is superior to that with 3.125% and 12.5% content of Ga. Ga-doping enhanced locality and strengthens bonding ability of electrons, which, to some degree, reveals electronic mechanism of Ga stabilizing δ-Pu. Character of Pu-Ga bond is metallic state, and interaction is mainly contributed by Pu 7s, 6p, 6d and Ga 4s, 4p orbital electrons. While interaction is relatively weak, doped systems maintain fine mechanical properties and machining performance. Contribution of Ga to stability of δ-Pu lies mainly in its improvement on bonding performance of Pu, instead of its immediate bonding effect with Pu.