Abstract: Knowledge acquisition technique gives constrains to study and application of knowledge system,therefore,effective extraction of domain knowledge from text becomes the major approach to knowledge acquisition.Domain knowledge acquisition technique based on theories of ontology and graph analysis is proposed,data structure of ontology,instantiation of ontology concept and construction of semantic field are discussed.Frame of text knowledge acquisition system is constructed,which is of general applicability,and the prototype system has been realized.By experimental verification of domain knowledge acquisition in Traditional Chinese Medicine,the system achieved good results.