Abstract: Combining SE-CCR model and DEA-BCC model, this paper evaluated and analyzed the relative efficiency of scientific research service of 20 university libraries in Jiangsu province. The empirical results showed that the efficiency of scientific research service in most university libraries was in a non DEA effective state, and the scale efficiency was the key to the improvement of comprehensive technical efficiency. In order to further improve the service efficiency of university libraries in Jiangsu province, it is necessary to adjust the scale of library resources input and strengthen the service ability of library discipline.