The purpose of the study is to examine the role of spatial ability and attention shifting in reading of illustrated science texts. Thirty-five fourth/fifth elementary students read two science texts. Prior knowledge and retention/transfer learning outcomes were measured using researcher-developed measures. While reading, students' eye movements were monitored with an eye-tracker. Several eye movement indices were used to reflect reading processes. Fixation count on text/picture was used to represent students' attentional focus on text or picture. Text to text saccades and picture to picture saccades were used to reflect students' information organization. Students' integrative reading behavior was measured by eye movement transitions between text and picture. Wisconsin Card Sorting Test and Visual Perception Skill Test were used to assess attention shifting and visuospatial working memory, respectively. Multiple regressions were conducted to examine whether students' spatial ability and attention shifting predict text processing, picture processing, or integrative processing of text and picture. Hierarchical regressions were conducted to examine whether students' integrative reading make unique and direct contributions to their learning outcomes. The study found that 1) both spatial ability and attention shifting are significant predictors for integrative reading behavior while they are not for other processing behaviors (i.e., text processing and picture processing) and 2) integrative reading behaviors in illustrated text reading account for significant amounts of variance in the transfer outcomes while not in the retention outcomes. This study gives practical implications on the development of visual literacy interventions and on how teachers design their instruction about science text reading.