This pilot study examined learning English vocabulary by an E-book from cognitive load aspect, and adopted eye-tracking data as a reference to investigate participants' attention distribution among learning targets, pictures and background graphics. An ASL Mobile Eye-XG eye-tracking system was used to record participants' visual behaviors in this study. A Wilcoxon test was conducted to compare the performance before and after the learning process. Correlation tests were conducted to examine the relationships among posttests, visual behaviors and cognitive loads. Also an ANOVA analysis was conducted to compare the total reading time spent on texts, pictures and background graphics. The preliminary results indicated that participants demonstrated a significant progression through reading the E-book. Besides, it was found that the participants spent more time on reading texts than pictures and background graphics. More details of the results will be discussed in the conference.