The structural, elastic and electronic properties of Pu2O3 have been investigated by means of the density functional theory using the full-potential linearized augmented plane wave (FLAPW) method and the local spin density approximation (LSDA) and the generalized gradient approximation (GGA) with on-site Coulomb repulsion U (LSDA/GGA+U) method. Our studies indicated the lattice parameters a0 and c/a of Pu2O3 are in good agreement with the corresponding experimental data, and elastic constants were reported in this article. At the same time, the density of states of Pu2O3 by LSDA/GGA+U appear 1.8eV and 2.2ev bandgap at the Fermi level, and LSDA/GGA calculation results in the formation of apparent contrast and therefore the U value of 5f in Pu makes the system change from a conductor to an insulator, which is in accord with the experiment. In addition, the charge density calculation results show that the charge density between Pu-O and LSDA is increased compared with LSDA+U, and it has obvious characteristics of bond formation.