Abstract: A nationwide sample screening of psoriasis was carried out in 1984. The mean annual incidence rates of psoriasis in urban and rural areas were 0.20‰ and 0.08‰ respectively. The mean annual incidence rate of psoriasis in China was 0.10‰ approximately. The annual incidence of psoriasis was significantly higher in areas northern to 35° north, latitude, in urban areas than in rural areas, and in males than in females (P<0.01). The annual incidente of psoriasis showed significant positive correlation with the annual prevalence of psoriasis and showed significant negative correlation with the mean temperature and the mean relative humidity during the year. The age-incidence of psoriasis reflected the age-liability to psoriasis more reasonably and reliably than the proportion of age at onset of psoriasis did.