Lattice parameters, atom positions and electronic structure of Pu-based superconductor PuCoGa₅ are studied with local spin density approximation (LSDA) and LSDA+U method of full potential linear augmented plane wave (FLAPW) method based on density functional theory. LSDA+U formalism was used to account for the strong on-site Coulomb repulsion among localized Pu 5f and Co 3d electrons. It shows that results of LSDA+U considering strong correlation between Pu and Co agrees well with relevant theoretical and experimental data, especially, PuCoGa₅ Pu-5f strong domain features of electronic spin down. In addition, orbital hybridization between Pu-5f and Co-3d is obviously stronger than that of Ga-4p.