Emergency care for mass casualty incidents is a sophisticated multi-participant process. To manage this process effectively, many information systems have been proposed. However, their performance in improving the efficiency and accuracy of patient triage is not satisfactory. This paper is concerned with the development of a mobile-based system for supporting emergency triage in the emergency care process for mass casualty incidents. This system collects the patient's emergency data throughout the whole emergency care process through a mobile application and data transfer mechanism. Using a Cox proportional hazard model, the system has the capacity to present the survival curve to the triage officer, helping him/her to make triage and transportation decisions. This system offers an alternative injury assessment tool based on the vital signs data of the injury patient. With the help of this system, the triage officer can more directly and comprehensively learn about each patient's situation and deterioration without additional operations at the incident site.