It is critical to understand how characteristics of environment influence human acquisition of spatial knowledge and wayfinding behaviors. The understanding provides insights for designing cognitively ergonomic wayfinding aids. Space syntax has been increasingly used in applications such as formal descriptions of environments and predicating wayfinding behaviors. From the perspective of cognitive geography, we review two popularly used methods of space syntax and relate them to the legibility of the environment. That is, how the elements of the environment aid the acquisition of spatial knowledge. The five elements of built environments in cognitive maps and the legibility of the environment are used as the theoretical frame to review each method. An exploratory behavioral experiment is designed to validate the formal descriptions produced by space syntax. Results indicate that different methods of space syntax have specific strengths on understanding knowledge acquisition and wayfinding behaviors in environment. Further directions of improving space syntax are also discussed.