The C6F12O molecule was optimized at different external electric field intensities (0000a.u.～0040a.u.) on the 6-31G(d) using the Minnesota density functional (M06-2X).The molecular structure,dipole moment and total energy of the ground state under different external electric fields were analyzed.Then,the excited state energy,wavelength,vibrator intensity and UV-vis spectrum of C6F12O molecules under various electric fields were studied by TD-DFT method.The results showed that the ground state and excited state properties of the molecule are dependent on the external electric field.As the external electric field increases,the total energy of the molecule gradually decreases and the dipole moment increases.The excited state energy of the molecule is generally reduced,and the C6F12O molecule becomes easy to excite.The absorption wavelength of C6F12O molecule increases from the ground state to the excited state and are mainly concentrated in the ultraviolet region.The vibrator intensity of excited state increases partly and the others decreases,and the variation is complex.With the increase of the external electric field,the absorption peaks at 132 nm and 162 nm in the UV-vis spectra are redshifted in the absence of external electric field.