Impulsive eating behavior is defined as experiencing a sudden and unplanned urge to eat when facing hedonic food that is immediately gratifying and then acting on the impulse without careful deliberation on subsequent negative consequences. In fact, impulsive behavior contains two counteracting processes: desire producing and self-control exerting as many researchers point out. Impulsive eating is one of the most important reasons of obesity, and obesity can cause cancer, heart attack and diabetes etc., therefore, studying the impulsive eating behavior is very important to fight against obesity. Reward sensitivity, a stable ‘psychobiological’ personality trait, is a source of impulsiveness and demonstrated by many studies to be related to food taking and overweight/obesity. Exploring the roles of reward sensitivity in impulsive eating behavior contributes to the deep understanding of impulsive eating behavior and providing ideas for solving obesity problem. The authors reviewed the dispersive relevant literatures about impulsive eating behavior and reward sensitivity, trying to provide a comprehensive understanding of the roles of reward sensitivity in impulsive eating behavior from the complicated, even inconsistent results of studies by organizing the literatures according to the processes of impulsive eating behavior: noticing hedonic food, producing urge to consume, exerting self-control. Firstly, the authors introduced the concept of reward sensitivity, the major research fields reward sensitivity involved in, and the biological basis of reward sensitivity. The authors also introduced the measuring methods of reward sensitivity including measurement of fMRI (functional magnetic resonance imaging) and ERP (event-related potential), as well as scale measurement; secondly, the authors analyzed the relevant literatures about the effects of reward sensitivity on impulsive eating behavior and proposed that there are three paths that reward sensitivity affects impulsive eating behavior probably: 1) a higher reward sensitivity could cause a more attention bias toward hedonic food cues, which implies that an individual with higher reward sensitivity could notice/see more hedonic food; 2) a higher reward sensitivity could lead to a stronger desire when facing a hedonic food; 3) a higher reward sensitivity could make self-control more effective. As shown from above, the mechanism is complicated underlying the effects of reward sensitivity on impulsive eating behavior, and an individual with higher reward sensitivity does not always behave more impulsively considering both the stronger desire and more effective self-control when facing hedonic food. Lastly, the authors pointed out that the further research directions of impulsive eating behavior from the perspective of reward sensitivity: firstly, to further explore the effects of reward sensitivity on impulsive behavior through attention bias, including: 1) to further confirm the attention bias from reward sensitivity using laboratory experiments considering the existing conflicting results about attention bias; 2) to test the influence of reward sensitivity on impulsive eating through attention bias in natural setting. Secondly, further studies are needed to explore the possible reasons that reward sensitivity affects self-control positively. According to the extant literatures, we proposed that individuals with high reward sensitivity may use different coping style to resist desire compared to those with low reward sensitivity, or maybe they have different level of goal-driving motivation.