Nowadays with the development of Internet, there is a shift from offline to online travel agencies. Challenges like customer loyalty go hand in hand with advantages such as fast speed and convenience. This paper aims to identify what are the determining factors that have an impact on customer loyalty to online travel agencies through an empirical study of Expedia, an online travel booking platform. According to the research of previous literature, this paper proposes seven factors that have an influence on customer loyalty in the environment of online travel agencies. Then a new framework is outlined and seven hypotheses are generated to address the research questions that are put forward. This study adopts an online questionnaire, a quantitative strategy, as the method to collect data. After analysis, the results support five outlined hypotheses and two are not supported. Finally, the findings will provide some managerial implications to improve the customer loyalty to Expedia and also be helpful for the whole online travel agency market.