Abstract: Researches were conducted on 5 natural populations and 2 cultivating populations of Coptis teeta Wall in Yunnan,and the phenotypic diversity of 20 characters was compared to reveal the phenotypic variation and variability of Coptis teeta Wallin in Yunnan.Phenotypic diversity within and among populations was analyzed by using coefficient of variation analysis,correlation analysis,diversity index and cluster analysis.The results showed that Coptis teeta Wall in Yunnan had a rich genetic variation both within and among populations.The coefficient of variation were different in 20 characters,the range of among the traits was from 10.9%75.1%,the average was 33.6%,the diversity index was between 1.6341.839;the degree of variation was different among 7 populations, the CV were between 27.4%37.1%,the highest was presented in population in Zizhi,Mingguang Village,Tengchong Country(TCZ),the lowest was in the population in Puladi Village,Gongshan Country(GSP).The mean phenotypic differentiation coefficient Vst was 74.405% within populations and 25.595% between populations,the results showed that the variations were mainly from within the populations.The investigated 7 populations of Coptis teeta Wall could be divided into three groups according to the UPGMA cluster analysis by the threshold as 1015,but the results were not based on geographic distance,and no obvious difference was shown between the natural and cultivating populations.