Abstract: The purpose of this research is to establish and optimize the quantization algorithm of the tourist guide signs designing for the complex road networks. The rating of tourist attractions, the amount of tourists, tourism scenic areas, the travel time from expressway exits to tourist attractions were taken as the influence factors of node demanding level for tourist attractions. Based on grey variable weight cluster theory, a division measure of guide demand for tourist regions was established,which provided the theoretical basis for choosing which tourist attractions should be guided by directional signs. Compared with the current research of considering solely the level of tourism scenic spots to classify the guide necessity, the established method considered the traffic attraction of the scenic spots, which is more aligned with the drivers' demand. Considering the total amount restriction of guide signs, the path constraints of not making turns from the exit to the tourist attraction, and the condition that all tourist regions should be guided at least once. A mathematical model was established by using the genetic algorithm to obtain the optimal inducing effect and the layout of tourist guide signs. The established method can provide the optimal layout of tourist guide signs.