GeoData Web service is an important way to achieve the integration and sharing of heterogeneous geospatial data at present. However, due to the complexity of GeoData and no sematic supporting Webservice discovery, it is very hard for data users to accurately find the GeoData WebService they really want. In order to make it easy for users to quickly and accurately find the GeoData Web Service they want in semantic level, this article firstly, constructs MetaData Ontololy, and uses MetaData Ontology to describe the related semantic information for GeoData Web Service. Then it comes up with a new way of computing the degree of semantic similarity among concepts based on Ontology. Finally, it realizes the automatic discovery for GeoData Web Service based on semantic matching. The experiment result shows that the way in this article can dramatically improve the accuracy and intelligence of GeoData Web Service discovery.