Methods based on hierarchical cluster analysis, numerical taxonomy was first applied to 13 kinds of Brachionus, Platyias militaris and Lepadella patella.A total of 45 characters was evaluated from specimens in 15 Operational Taxonomic Units (OTU) .The results of hierarchical cluster analysis show that relation and the taxonomic position of 13 (OTU) kinds of Brachionus, Lepadella patelle and Platyias militaris.It was so concluded that Platyias militaris and B.diversicornis was assigned to Brachionus.The results of numerical taxonomy could objectively reflect the taxonomic position of Brachionus.