Abstract: Talking the library of Yunnan Agricultural University as an example, this paper analyzes efficiency and determinants of university library form from input and output, calculates and analyzes 3 comprehensive evaluation indexes of the library, through comprehensive benefit evaluation method, some problems are discovered. On this basis, this paper puts forward 4 aspects countermeasures, including controlling expenditure strictly, optimizing the structure of library collection, establishing cross-database search platform, and perfecting service attitude.