The botanical Origin, macroscopical and microscopical characteristics and physical chemical tests for the idcntification of Tianhusui (Hydrocotyle sibthorpipides Lam. ) and Potongqian (H.sibthorpioids Lam. var. batrachium(Hance) Hand-Mazz.) were reported to provide abasis for the identification of the drug and revision of the drug standard.