While libraries become digital, digitization becomes more and more crucial affecting libraries. This study investigates current practice of digitizing library materials in the US. Building a good digital collection has been a common task pervasive in all types of libraries. With challenges that pose the most significant problems or concerns for libraries in digitization practice, researchers and practitioners would like to know what practices have been developed to deal with them? Through probing some widespread issues on what materials to digitize and associated standards and technologies in digitization in the United States libraries, this survey of current literature reveals a number of prominent library digitization practices, methods and challenges, and highlights the best practices, trends and interests in library digitization pertaining to both policy and technology marketplace issues.