Digital reference services have been a key role in academic libraries in the context of various digital environments. The guidelines for the digital reference service are one of important aspects to improve the quality of services and system design and implement better services. In this study, by case studies and a questionnaire survey for academic librarians, the guideline for the digital reference service is suggested with three phases; plan, operation and evaluation. The guideline for the digital reference services suggested in this study is expected to support digital reference services in academic library environment.