The paper introduces the current situation of study on medical termindogy standardization in and outside of China, analyzes the building procedure of medical term system and key problems in the study on terminology standardization, discusses the building framework and procedure of medical terminology system with systemic analysis method, and points out that in the building of medical terminology system, several problems shall be focused on, including selection of medical terminology, building of material library, establishment of conceptual system, standardization of terminology, open release and application maintenance.