Morphological variations among four geographical populations of Sanguinolaria diphos were analyzed using three multivariation analysis methods using 7 morphometric proportional parameters.The results of clusters analysis and principal component analysis show that Qinzhou and Beihai populations,Zhanjiang and Lianjiang populations were morphological similar,while Beihai and Lianjiang populations were quite different.The contribution rates of the first,second and third principal components(P₁,P₂ and P₂) were 38.395%,27.653% and 20.224%,respectively,and the cumulative contribution rate was 86.272%.Resultsof discriminant analysis show that the morphological differences of the 4 populations were significant(P<0.01).Discriminant functions of the 4 populations were established,and the discriminant accuracy rate of P₁ and P₂ were from 73.30% to 90.00% and from 73.30% to 90.00%,respectively,and the comprehensive discriminant accuracy rate was 79.18%.Resultsof correlation analysis show that there were significant correlation between the Euclidean distance and the geographical distance(r=0.669 9).