This study was concentrated on how useful the en route information display system for firefighters’ information accessing, current situation understanding, and decision making, we did a series of tests to investigate the efficiency of the system, to compare different display ways including audio, text, and their combinations to find the most appropriate one. The result showed that: (1) Audio only always made firefighter taking the longest time to information detection, but the introduction of audio display made the two combined displays (text + audio, and text + 3rd level audio) more quickly to access information, and more easy to remember. (2) It should be clarified that en route system could be used very well either in quiet and static environment, or in a moving and a little bumping environment if user could get some training before using it.