The purpose of this study is to construct a model for measuring and assessing service quality in public libraries based on the theory of service quality in marketing area. Firstly the degree of importance of service factors is measured and ranked according to the value of each factor. This importance ranking indicates the order of service improvement. Secondly the correlation model between service factors and customer’s satisfaction and behaviour is established and verified in statistical method. The result shows that the order of service quality factors which have influence on the customer’s satisfaction and behaviour is the order of service quality factors required preferential improvement.