The structural optimizations,molecular vibrational modes,vibrational frequencies and intensities of phosgene are calculated by using Restricted Hartree-Fock(RHF) and Density Functional Theory(DFT) at levels of RHF/6-31G,RHF/6-31+G,RHF/6-31++G,RHF/6-311G,RB3LYP/6-31G,RB3LYP/6-311G,RB3LYP/6-31+G,RB3LYP/6-31++G,RB3LYP/6-31G(d),and UB3LYP/6-31G respectively.The research results show that,the theoretical calculations agree well with experimental data,and DFT RB3LYP/6-31G(d) basis set may obtain the best calculat...