Carrier gas mixing as one of the most important methods to improve the separation ability of high Field Asymmetric waveform Ion Mobility Spectrometry (FAIMS) has been widely used in the field of bio macromolecule mass spectrometry, while there is a lack of some research in environmental small molecules. In this paper, five typical volatile organic compounds (VOCs), including o-xylene, isobutanol, n-hexane, acetic acid and acetone, were chosen to study the effect of N2-He mixing ratio on the peak position, resolution and ion pass rate of monomers and dimer ion. The results showed that with the increase of the proportion of He in the carrier gas of FAIMS, the peak position of the monomer and dimer ion in five VOCs shifts, and the peak of the monomer and the dimer were different, and the monomer peak shift increased first and then decreased, while the dimer peak position shift increased gradually. With the increase of the percentage of He, the resolution of FAIMS for aliasing peaks of five VOCs gradually increased and tended to saturate at last, where the saturated helium ratio was: 20%, 30%, 10%, 40% and 20%, respectively. In addition, with the increase of the percentage of helium, the signal intensity of o-xylene, isobutanol, n-hexane and acetone had no obvious change, while that of acetic acid decreased significantly. This study provided a feasible method for improving the separation ability of FAIMS and validating the effectiveness of Blanc’s law under high electric field applied in the field of small molecules.