Concept of city square was introduced and believed as an important component of urbanlandscape and also a major space for urban residents’ activities. Beauty of city square lies in the interactionbetween environment and social behaviors. By introducing the two-way interaction between city squareand users, behavior psychology was proposed as the foundation of environment design of plaza. Asmore and more attention is given to human-centered design of outdoor spaces, environment psychologyhas gradually been more applied in the design of various urban landscape spaces. In view of problemsin the present square design, relevant theories of environment psychology were introduced to analyzepsychological needs and behavior characteristics of people in outdoor spaces, and techniques for human-centered designs of city square explored to build public spaces for city dwellers.