The public buildings and facilities investigated in this paper have disaster prevention signs, but they have the defects such as non-uniform, having gaps and unsystematic. The human subjective initiative of disaster prevention signs lays in the sign cognition which is influenced by many factors. In this paper, comprehensive investigation has been taken, and the relevance between disaster and sign cognition has been analyzed. A new perspective that cognizance regions are classified as risk, transitional and safe is proposed. Besides, the ways of setting up signs according to different regions have been researched. These contributes to the cognition of disaster prevention signs.