As an important branch promoting the overall development of medicine in China, special medicine has accumulated many multi-source heterogeneous data since its emergence, but how to accurately analyze and efficiently apply the knowledge is still an urgent problem. Knowledge graph has the advantages of structured organization, management and application of massive big data to achieve knowledge reasoning, and it is a key technology to promote medical digitization. This paper mainly discusses the advantages of knowledge graph in knowledge association to solve the problem of data processing and application in special medical field, summarizes the key technologies involved in the construction of medical knowledge graph, analyzes the progress of knowledge graph in various branches of special medical field, and finally discusses the limitations and directions of knowledge graph in a sub-field of special medicine-cold region medicine.