How to improve the quality of library mobile services and adequately meet the needs of users has become the foremost challenges for libraries. This paper obtains users’ evaluations of mobile library services by field interviews,summarizes their viewpoints based on grounded theory,and constructs an evaluation model of user perceptions. A survey questionnaire is designed to obtain sample data from university students and an empirical analysis has been conducted. The factors affecting the perceived quality of library mobile services are identified as follows: environmental quality(including network facility, interface design and social impact),interaction quality(including interaction channels and professional capabilities),information quality(including personalization and relevancy),and search quality(including comprehensiveness).