The electronic cigarette (e-cigarette) marketing is unregulated on social media currently. Flavor is one of the potent marketing strategies for ecigarette manufactures and vendors. In this paper, we investigate the flavorrelated e-cigarette marketing and online users’ response to flavor-related e-cigarette marketing in Facebook. We find that the fruit flavor is most frequently promoted on social media e-cigarette marketing with a share of 33.19%, followed by nut (17.72%), candy & sweet (9.28%), alcohol (7.43%) and menthol (6.75%). With regard to the users’ response to e-cigarette marketing, 85% of comments on flavor-related content (FC) happened within 84 h, while it is 243 h for 85% comments on content unrelated with flavor (named as miscellaneous content, MC). Furthermore, the ratio of positive content to negative content in FC (RFC) is 1.4857; while RMC is 0.8801. According to this work, we conclude that flavor plays an important role for online e-cigarette marketing with the boosting of user interaction and positive emotion.