β-phenylethylamine (C6H6-CH2-CH2-NH2, PEA) is one of the simplest neurotransmitters in biological systems. In this paper, conformations of liquid PEA have been explored by mean of Raman spectroscopic and density functional theory (DFT) calculations. The Raman bands of PEA were roughly assigned by the assistance of previous studies and the theoretical predictions. We compare the experimental Raman spectra (at room temperature) and theoretical Raman spectra of all conformers of PEA. The results indicate that six conformers could coexist in the liquid PEA. The temperature dependence Raman spectra of liquid PEA was recorded. The results imply that the anti-conformer was more favorable than the gauche conformer in the liquid PEA at room temperature, which may due to the intermolecular hydrogen bond formed in the anti-conformers.