In digital environment, the hallmark of the national libraries is its responsibility or function of acquiring and preserving the country’s off-line and on-line publications in term of legal deposit. But the legal deposit system based on print materials in Korea predates the digital age and requires a new legal framework. It would be a tragedy if national library was not to archive the nation’s intellectual and cultural heritage because of limitation of legal deposit system. The purpose of this paper is to analyze form of the current deposit system and to suggest a reform model for legal deposit legislation with priority given to legal scheme and elements(terms, the depositor, the depository, object of deposit, number of copies, time of deposit, compensation and fine, right of migration and free access, etc.).