The investigation of the emergency care of the mass casualty incident caused by Kaohsiung Gas Explosion was conducted in this study. The results show that the triage system and triage tags were seldom used by first-arriving crews and the patients were often transferred directly to the hospitals rather than the emergency treatment areas. In order to increase the operating efficiency of triage and shorten the rescue time, this paper has analyzed the difficulties that emergency medical technicians confront in the mass casualty incident. The results of this paper will improve the on-site rescue efficiency.