Customers always have the tendency to avoid uncertainty, but more and more corporations utilize uncertain promotion as a strategy in marketing activities, and deliberately give consumers a sense of uncertainty. The theoretical academic analyzes this interesting phenomenon from different perspectives to test the effectiveness of uncertain promotions. This paper makes a systematic review of uncertainty promotion research during the past twenty years. At first, it concludes the mechanism of the effects of uncertain promotions from three perspectives, namely information gap theory & internal driving force theory, positive feeling theory and innate optimism theory. Then it also recognizes the utility boundary of uncertain promotion from the perspectives of consumption goal, promotion strategy and consumer characteristics. Last but not least, this paper discloses future directions in uncertain promotion research.