In fire situation, we have to consider factors affecting sign's visibility such as power failure, obscuration by smokes, and smoke adhesion to the sign surface or light sources. It is necessary to establish a calculation method of luminous stimuli in fire smoke to evaluate evacuee's visibility quantitatively. This paper proposes a calculation model of target luminance in fire-smoke taking into account of smoke adhesion. By incorporating this model into "Two Layer Zone Model" which predicts the effects of the fire development inside an enclosure of fire, we can express the evacuee's luminance distribution under any transient fire and smoke conditions.