Abstract:The wild Echinochloa plants are representative weeds in rice field, agronomists have tried to elucidate their morphological and ecological characteristics. But the cytological study is still lacking. This paper deals with the chromosome morphology of 7 spcies and varieties of this genus.This study showed that the chromosome numbers of root tip cells in the analysed species of Echinoloa were 2n=36 or 54. The karyotypes in the analysed 6 species were as follows:E. crus var. crusgailli 2n=54=48m+6sm; E. crus var. zelayensis (H. B. K.) Hitchc 2n=54=42m(2SAT)+12sm(4SAT); E. crus var. mitis (Pursh) Peterm 2n=36=24m+12sm(2SAT); E. cruspavonis (H. B. K.) Schult 2n=36=34m+2sm(2SAT); E. caudata Roshev 2n=54=42m+12sm(4SAT); E. hispidula (Retz.) Nees 2n=36=24m(2SAT)+10sm; E. glabrescens Munro ex Hook. f. 2n=54=44m(4SAT)+10sm(2SAT); E. oryzoides (Ard) Fritsch 2n=54=48m+6sm(2SAT). The chromosome numbers and the karyotypes of these species and varieties were reported in China for the first time.