The invention relates to a method for analyzing nicotine optical isomers in an electronic cigarette liquid by using a positive-phase liquid chromatography-tandem mass spectrometry method. The method is characterized in that the nicotine optical isomers in the electronic cigarette liquid are separated by a chiral chromatographic column, a post-column high pressure liquid output pump is used for introducing isopropyl alcohol and separating flow, and the tandem mass spectrometry is used for analyzing. The method has the beneficial effects that (1) the nicotine optical isomers in the electronic cigarette liquid are analyzed by the positive-phase liquid chromatography-tandem mass spectrometry method, so as to separate and detect the nicotine optical isomers in the electronic cigarette liquid; (2) the post-column high pressure liquid output pump is used for introducing the isopropyl alcohol and separating flow, so that the amount of non-polarity solvent entering mass spectrometry is reduced, the amount of the isopropyl alcohol of polarity solvent is compensated, and the ionizing efficiency is improved; (3) compared with the prior art, the chromatography resolution of the two types of nicotine optical isomers is high, and the difference of retention times is 1min; the analysis time is short, and is only 17min; the sensitivity is high, and the quantitative detection of lower content of R-(+)-nicotine in the cigarette liquid can be realized.