Abstract: In 1984, a nation-wide large scale survey of psoriasis was carried out in 53 cities and rural areas, distributed. in 24 provinces, municipalities and autonomous regions according to a planned programme. In a total population of 6,617,917, there were 11,393 psoriatic patients discovered. The prevalence rate was 1.23‰,with a preponderance of male over female. The prevalence was higher in the northern part of the country and lower in the southern, for instance, it was 4.20‰ in Dehui County of the northern Jilin Province and 4.86‰ in residents of Beijing Capital Steel Plant, while it was 0.04-0.07‰ in rural areas of southern Guangdong Province. The prevalence of psoriasis of urban population was as a rule higher than that of the rural.