Library information ecosystem is designed to maximize the satisfaction of the users and gradually optimize the library service system, so as to constantly innovating its service function and maximize the value of the service system. Seeing from the traditional library service system, the cognizance of service principal and environment is narrow, and the relationship between services is simple, thus, the library service system can't meet users' requirements to information resources. This essay focus on the exploration and research process of knowledge services, making the ecological service thought integrate into the construction of library service system. Besides, it also illustrates the inner relationship between ecological niche and information space, and systematizes the construction of ecological service chain, so as to idealize the construction of information ecosystem. Through the research of system construction and function dimension, this essay is designed to lay a solid foundation for the exploration work in the future.