Digital library construction needs knowledge organization technologies support. In this paper, we probe into the technologies from three dimensions. The grammatical technologies include metadata, XML, RDF and etc. This type mainly focuses on how to describe data efficiently in terms of the outer characteristics of data. The semantic technologies include Topic map, Ontology, semantic web and etc. They mainly describe the content of data, finding the relations between each other.The pragmatic technologies include grid, database and etc. They want to control the information, and make it used efficiently.