The National Library of Singapore is both a national library and a public library. As a national library, its responsibilities include collecting comprehensive books and materials needed by the public, becoming the national repository of Singapore publications and publications of various countries in the field of Singapore studies, and providing reference services, interlibrary loan, exchange and reproduction services. Its unique research collection in Southeast Asia is open to local and overseas scholars and researchers.

As the national bibliographic center, the National Library of Singapore compiles national bibliographies, periodical indexes and various joint catalogues. Publish "Singapore National Bibliography" and "Singapore Periodical Index". At the same time, the National Library of Singapore is also the central organization of Singapore's comprehensive library automation service network, which is also a national bibliographic network, providing joint catalogs for member libraries; The National Library is also the international project center of ISBN and ISSN.

As a public library, the National Library of Singapore has more than a dozen branches scattered all over the country, which undertake the functions of its public library. The first branch library was built in Queenstown on 1970, and the latest service outlets have developed into large shopping centers.