The molecular structure optimization and characteristic spectra of Freon-12 and its substitute of Freon-134a are obtained by density theory (B3LYP/6-311G++(d,p)) calculations.The molecular configurable parameters,including bond length,bond angle and dihedral angle are calculated through high precise computation.The IR spectra and the Raman spectra of these two molecules are obtained by further calculation.The calculated IR spectra of Freon-12 are in good agreement with experimental results taken from National Institute of Standards and Technology,which proves to be accurate.Additionally,we get the UV-VIS spectra of Freon-12 and Freon-134a by calculating energy with CIS method.The computing results offer useful reference for protecting atmospheric ozone layer.