Abstract: The karyotype of Cladocera Daphniopsis tibetana Sars collected from north Tibet was studied using larval parthenogenetic females. The results showed that the chromosomal number of D. tibetana is 2n=24. According to Levan's standard, the karyotype of D. tibetana is 2N=6M+18T and compared with Moina and Daphnia. The relationship among three Cladocera and the evolution position of D. tibetana were discussed.