Abstract: Online community information service in public library of China belongs to a kind of innovative service model.This paper analyses the key factors influencing the online community information service of public library based on diffusion of innovation theory .Among these factors, relative advantage,compatibility,triM, observability,communication channels,nature of the social system,extent of changing agent＇s promotion effort,innovation-decision type exert a positive influence on community information service development.In contrast,the factor,complexity,exerts a negative influence.Based on above analysis,it is reasonable to believe that the online community information service of public library will develop fast in China.

Key words: online community information services;public library;diffusion of innovation theory;China