Abstract: The population ecology of Ranunculus bungei Steud.was investigated in a rapidflowingstream in North Temperate from 1986 to 1991. The distribution pattern and the age structureof the plant population, and the periodic change of the population size are reported,and soare the static life table and the fecundity schedules.The survival curve and the Overwinteringcurve as well as the innate capacity for increase are presented.The logistic curves are simu-lated for the curves of the population size and the number of individuals by reproduction ofthe population, Changes of the population size are discussed in relation with emigration andimmigration proeesses.