Abstract: Liquid crystal is one of important materials. It has been widely used in physics, chemistry, electronics and so on. Because of its particular characteristics, more and more chemists have been attracted to it. Surprisingly, there are only a few papers on electroionization mass spectra of liquid crystals. In this paper, the chemical ionization, electroionization mass spectra of liquid crystal of phenyl benzoates are presented. The molecular ions of their EI mass spectra are very weak or absent, but they are very strong in CI mass spectra. So we can obtain the structural information of the liquid crystal of phenyl benzoates combined CI spectra with interpretative EI spectra.