119 -The objective of digital preservation is to ensure that digital information survives in usable form for as long as it is wanted. That is to ensure long-term access to digitally stored information. The preservation of digital objects involves a variety of challenges, including policy questions, institutional roles, legal and rights issues, metadata, and technical strategies. In this paper, I introduce the definition of digital object, life-cycle of digital object, and related archiving workflow which are basic concepts of digital archiving. Also I focus on the aspects of current techniques used in digital information preservation including technology preservation, emulation, refreshing, migration, encapsulation.