Abstract: The auther holds that the modem reference service,involved many factors,is a systematical engineering,but the reader＇s demands,reference collection,facilities and librarians are the four major elements among others and only attaching great importance and giving full play to the actio of the four major elements can reference service very fruitful and provide vigrous intellectual impetus and mental support to the economic and social development.

Key words: Reference Service,Reader Demands, Reference Collection,Facillties ,Librarians,Modem Library