Eye-tracking technology has been increasingly utilized as a research tool in educational studies in the last decade. However, analyzing eye-tracking data is usually a challenge for educational researchers. This study developed a tool, Eye-tracking Data Analyzer (EDA), for educational researchers to conduct advanced eye-tracking data analyses. With a graphical user interface, the EDA was developed by MATLAB programming. As a sample module of EDA, the development, interface design and validation of a lag sequential analysis (LSA) model were introduced. The LSA module in EDA provides a useful and convenient tool for educational researchers to quickly and deeply explore and illustrate learners' visual-attention transitional patterns during learning process. Implications and applications of the module are also briefly discussed in this study.