The effect of the oil spill dispersant (OSD) in the laboratory is mostly evaluated by testing the emulsification of the OSD at present. Test value of dispersing effect in the laboratory is generally higher than the value in the actual field. Mainly because a part of the spraying oil spill dispersants (OSDs) directly get into the water without a full role with the spilled oils, which not only reduces the overall dispersion effect, but also increases the cost of handling the oil spill and the secondary contamination to marine environment. Therefore, the total number of the OSDs that actually exists in the oil should be considered to evaluate the effect of a certain OSD, and the miscibility of the oil with the OSD should also be considered. Aim at the demand for testing the total number of the OSDs in the oil, this study has explored the feasibility of an analytical method of the total number of the OSDs in the oil using the gas chromatography (GC). First, the characteristic peaks representing these two substances in the GC had been found. Secondly, standard curves were made with the relationship between the two characteristic peak ratios and the mass ratios. Finally, the most appropriate characteristic peaks of the OSD and the oil were selected, with which a better standard curve was also selected, considering the role of weathering at the same time, which are used to test the relative total number of the OSDs in the oil spill.