The LED technology is continuously booming in recent years.The high luminous efficacy,long lifetime and flexibility of intelligent control bring LED application to the forefront in the competitive battles with traditional light sources.However,in the outdoor lighting especially in road lighting,there is rising concern that LED based light sources may cause more glare perception to the end users including drivers and pedestrians.Glare can result in the increasing detection threshold of the objects’ motion nearby and decrease the luminance contrast between the objects for detection and the background,which lead to increasing traffic unsafety.There are two main kinds of glare in road lighting,the disability glare and discomfort glare.Studies on glare show that the problem of discomfort glare is more difficult for solving than disability glare which can be demonstrated by the physiology of the human vision system well.So a method to estimate the discomfort glare form LED road lights is in urgent demand to guide the design of road lighting.