Abstract: As the country with the highest proportion of aging population in the world, Japan takes the leading position in the construction of a barrier-free city environment for vulnerable groups including the elderly, the sick, and the disabled, to travel around. Four elements-infrastructure, systematized planning, information design and service-make up Japan's barrier-free environment system. Reasonable and complete barrier-free infrastructure is the foundation of the system. Systematic planning focusing on merging into the environment connects the infrastructure effectively. Information system is designed with the idea of universal design, and service is used to cover the deficiency of the system. The promotion mechanism of Japan's barrier free environment construction, which has the completed design regulations system as the cornerstone, and the barrier-free facility construction of key development districts as the means of implementation, tries to improve public consciousness about building a barrier-free environment and develop a good social environment. Effective mechanism construction is the most important force driving the construction of a barrier-free city environment in Japan.