In the era of the Internet,libraries of universities and colleges have changed from the traditionalcollection of paper books to digitization quietly.Library digitization involves the whole process of informationresource processing,storage,retrieval,transmission and utilization.Digital libraries are virtual libraries,withoutwalls.In this free atmosphere,people can be free from geographical and time constraints,and have quick andeasy access to effective information.At present,there are still some problems in the construction of digitallibraries of universities and colleges,and three principles f...