Abstract: [Purpose/Significance] A library portal website is related to the function and social image of a library. Library website construction is also one of the tasks of the development of library cause in China during the 14th Five-Year Plan period. However, the website construction level of small and medium-sized libraries at and below the county level in China is relatively low, and effective measures are urgently needed to improve it. To this end, Japanese libraries' experience is worth learning about. Therefore, we take the websites of the municipality libraries in the Tokyo Metropolitan Area as the research objects to explore the information construction and design concept of the websites of small and medium-sized libraries in Japan, so as to provide suggestions for the improvement of the website of grass-roots libraries at and below the county level in China. [Method/Process] Firstly, we analyzed and expounded on the construction principles of small and medium-sized library websites in Japan. Then we conducted a network survey on the website construction of the libraries in Tokyo and summarized the information construction and design concept of the websites from the three aspects of website structure, UI, and function design. In terms of website structure, we investigated the design of navigation, retrieval (simple retrieval, advanced retrieval, and bibliography recommendation), regional data area, juveniles' pages (children's page, teenagers' page), mobile terminal, etc. In terms of UI, we investigated interaction design, color matching, visual identity, etc. In terms of functions, we focused on exploring the accessibility services, business support services, and education support services of the websites based on the concept of a "problem-solving library" in Japan. [Results/Conclusions] The structural design of Japanese small and medium-sized libraries' websites is oriented to the convenience of the people and pays attention to the needs of children and the regional cultural characteristics. The UI design is simple and intuitive, the color matching is soft, and the visual identity is clear. Their functional design focuses on problem-solving, especially in accessibility, business, and education support services. Therefore, according to the theory of responsible innovation, this paper puts forward four suggestions for the website construction of small and medium-sized libraries in China: (1) to be focused on local characteristics and strengthening the construction of local information resources; (2) to take users as the center to meet the diversified cultural needs; (3) to optimize basic services and improve service convenience and ease of use; (4) to rely on the general-branch library system to ensure operation to achieve sustainability.

Key words: Japanese library, small and medium-sized library, library website, information service