“Internet plus” is transforming human society in all aspects. As an important public service provider to library users，the library must also transform and upgrade the service to keep up with the times and meet the changing needs of its users in the Internet era. This article analyses the two major factors behind library service transformation and upgrading，discusses three characteristics of library service upgrading，and identifies the four problems facing the upgrading of library service in the era of “Internet plus”. The author also proposes the optimal path of the service upgrading of “Internet plus” era.