Abstract: Ground state of plutonium dioxide in electric fields ranging from-0.005 to 0.005 a.u. are optimized using density functional theory DFr/B3LYP with SDD for Pu and 6-311 + G^* for O. Excitation energies in electric fields are calculated with time-dependent DFT method. It is shown that electronic state, total energy, molecular geometry, dipole moment and excitation energy are strongly dependent on the strength of applied electric field. Dependence of excitation energies on applied electric field strength agrees approximately with that proposed by Grozema. Spectra of the first five excited states are in the region of visible-infrared-far infrared with wavelength ranging from 501.47 to 10 291.5nm.