Emergency room process is very important in the whole hospital processes because it is first diagnosis for patient. Above all, triage is important activity which quickly diagnose the status of emergency patient and sets the priority for treatment. This paper analyzes the treatment process pattern by triage type. The results show that the treatment process after triage such as residence time, diagnosis and checkup type, and joint treatment are dependent on triage types. We can use these analysis results for improving the current triage system and developing the new triage system considering a domestic emergency medical service environment.