Abstract:Six populations of Setllaria media and S.apetala and their 57 charaters have been clustered by means of Q-analysis and R-analysis. The results show that (1) In Q-analysis, 4 populations of S. media and 2 populations of S.apetala can be divided into 2 groups by combined line. This result supports the opinion that S.media and S.apetala should be treated as two species.(2)In R-analysis, the characters of complete positive correlatio, great positive correlation and great negative correlation have been found. In terms of a combined lines, 57 characters are clustered to 5 groups. The taxonomic significance of these characters has also been analyzed.