Abstract: The psychical process of drivers perceiving traffic signs is analyzed based on the knowledge of cognitive psychology, and an information process model for drivers, which combines the intuition, analysis and inference of drivers, is proposed. From the features of signs and drivers, a psychological-perception-based theoretical analysis is made on the factors influencing the traffic sign comprehension. The study results provide foundation for the study of cognitive process of drivers, the selection of evaluation index of signs comprehension effectiveness and the development and design of related systems.