Speed and speed variance are related to the intensity and the number of traffic accidents, and the effective control on speed and speed variance is the key to enhance the road safety. Perceptual speed reduction technology is "human-oriented", which has several merits such as the low cost, initiative and so on. The article explains the research significance of perceptual speed reduction; induces the concept of perceptual speed reduction; and analyzes the mechanism of its process and the basic characteristics of perceptual speed reduction, summarizes recent research status quo on this topic from several perspectives, such as hypothetical premise, experimental condition and method, conclusion and so on, meanwhile the paper carries on the classification of perceptual speed reduction, and analyzes advantages and disadvantages of each technique. Based on the above review, some important scientific questions which need farther study are raised and the future developing direction of perceptual speed reduction is discussed. Finally the research and the application prospect of perceptual speed reduction are given.