Four amino cobalt phthalocyanine is a promising photosensitizer, so the study of its spectrum is of great significance. The density functional B3LYP/3-21G* method was used in optimizing the structure of the four configurations of four amino cobalt phthalocyanine, which can calculate the energy of its most stable structure and infrared spectra in a simulated way. It is concluded that the simulated infrared spectra and the vibration obtained from experiment are in good fitting.