Prospective memory (PM) refers to the ability to remember to execute a delayed intention in the appropriate context. Everyday examples of PM tasks are remembering to buy bread on the way home, to take medication every evening at the same time, and to join a meeting at a specific time. More and more researchers begin to focus on the aftereffects of PM. It is defined as the phenomenon that an individual repeatedly performed an already completed PM intention, or the completed intention has an influence on the performance of the ongoing task. Researchers usually use the Repeated PM Cue Paradigm to investigate the aftereffects of PM. It contains two phases: active-PM phase and finished-PM phase. In the active-PM phase, participants are instructed to make a response whenever they encounter a target cue, which occurs very infrequently during an ongoing task. Following an active-PM phase, participants engaged in a finished-PM phase. Importantly, prior to the finished-PM phase, the participants had been instructed that the PM task was finished and that they would no longer need to press the designated key in response to target cues. The target cues continued to be presented during the finished-PM phase, and commission errors were observed. The aftereffects of PM have a negative impact on daily life, such as an individual accidentally taking an important medication twice. Most studies have found that this phenomenon is particularly prominent in the elderly. Older adults may be at a higher risk of making commission errors than young adults, although the sparse evidence to date is mixed. In recent years, researchers have discussed the factors that influence the aftereffects of PM between the old and the young from both internal and external perspectives. It has been learned that the decline of the inhibitory control ability and short-term memory deficit brought about by cognitive aging are the main factors which result in the different aftereffects of PM between the young and the old. In addition, other internal and external factors also exacerbate the age difference in the aftereffects of PM. Although the existing researches have discussed the factors affecting the age difference of the aftereffects of PM, these do not reveal the mechanism of it between the young and the old. From what have been mentioned above, cognitive aging leads to the age difference in the aftereffects of PM, and the discussion of related contents about the aftereffects of PM are not enough. Future studies are required to expand the understanding of the mechanism of cognitive aging and inhibitory control ability. In addition to this, there are many researches using brain imaging techniques such as ERPs and fMRI to explore the PM. So far, these techniques have not been used to investigate the aftereffects of PM. Researchers should use the brain imaging techniques such as ERPs and fMRI to reveal the neural mechanisms underlying the aftereffects of PM in different age.