The computerization is advanced now with a lot of hospitals. The input of the medical information is a load of the doctor because it doesn’t convert it easily because the medical treatment term is a special word. The dictionary is very important. Because the conversion efficiency improves when the accuracy of the dictionary is high, the doctor’s load can be reduced. This research developed of medical treatment dictionary of each diagnosis and treatment department. Moreover, medical treatment dictionary of each diagnosis and treatment department doesn’t use information on the word used by other diagnosis and treatment departments. It is thought that it becomes doctor’s awareness and study by presenting the word that other diagnosis and treatment departments used when converting it. And, the relations between diagnosis and treatment departments that examine the lung cancer and the relations of the word used by each diagnosis and treatment department are visualized by using. Then, the relations between diagnosis and treatment departments are investigated. As a result, it has been understood that the word used by the diagnosis and treatment department is different though the same disease is being written.