Abstract: This article is a study on the scientific name of the chinese me-dical plant "yanhusuo". By 1977 it had been named three times.Formerly, it was named as Corydalis bulbosa DC. for a long time.Later a name, Corydalis yanhusuo W. T. Wang, was given. And then, another name was given to it. That is to say it was Cory-dalis turtschaninowii Bess. f. yanhusuo Y. H. Chou et C. C. Hsu.All these names were studied in this article. First, the research history of "yanhusuo" was refered to second, a series of investigation was carried on with the population point. And finally, it was expe-rimented by cultivating. It has been planted in Heilonjiang piovince and the morphological expression was observed. Through these stud-ies, some primary conclusions have been obtained as follows. Its stem is not simple and it is not protruded at the bose of the lower one of the outer petals. These characters are different from Corydalis bullosa DC. which is endemic in Europe. Thus. "yanhushould not be namec as C. buldcsa DC. The flower of "yanhusuo" possesses not only two conspicuous mem-branous sepals which are not caduceus but also root-stocks which are usually more than one. Each node of the root-stocks has a scale leaf and forms a tubercle. All these facts made us regarad "yanhusuo" not as a forma of Corydalis turtschanincwii Bess., because it does not have such characters. These characters:"cum 2 sepalis membranacetis, rhizomatibus tub-erculibus ad nodos", only belong to "yanhusuo". And they are closelycorrelated with the cultivated condition. So we consider "yanhusuo" to be another species which is to be better to be name as Corydalis yanhusuo hort. ex W. T. Wang.