Library automation has been developed for 30 years nearly in Taiwan since 1973. after a serious literature review on the topic of library automation evaluation in Taiwan, only several papers have been discussed, but most for them focus on case study. This paper aims to construct a standard evaluative model for library automation system both for selection and usage. The proposed model is composed of four key components by follows: identifying the past and current trends, four facets and related content of evaluation model, evaluation principles, methods and criteria, as well as the model is exemplified into four stages. Finally, additional five issues are raised as a conclusion: cost benefits and efficiency, risk distributed, partnership relation, and librarians' skills and ability.