The invention relates to electronic cigarette liquid and a quality detecting method. The raw materials of the electronic cigarette liquid are cigarette industry finished cigarette tobacco supercritical fluid extracting substances, other components are added, even mixing is carried out according to weight percentage, and then the liquid is prepared. According to the formula, the liquid comprises 10%-30% of finished cigarette tobacco extracting substances, 5%-15% of tobacco flavor, 2%-10% of deionized water and 10%-30% of glycerine, and the rest is propylene glycol. A gas chromatography-mass spectrography method is used for analyzing the extracting substances, a chromatographic peak area normalization method is used for determining the relative content of various volatile components, and according to the key chemical components which determine characteristic aroma style and the magnitude of the relative content, the quality of the electronic cigarette liquid is evaluated. According to the electronic cigarette liquid, the cigarette finished cigarette tobacco supercritical fluid extracting substances are used as main components, the aroma and the taste of an electronic cigarette are made similar to the taste and sense judgment of a traditional cigarette to the maximum degree, and the problem that single cigarette regulated cigarette liquid taste is single and is not harmonious is solved. Meanwhile, cigarette liquid flavor component evaluation is objective and accurate through the gas chromatography-mass spectrography method.