Abstract: The design of human-machine interaction systems should be adapted to accommodate changes in user search tasks. This study aimed to enhance user interaction efficiency by investigating the behavioral variances among users employing different interaction modalities during operational tasks. A mixed experiment design was used, involving three modalities (touch, voice, eye control) and two task types (operation-fuzzy, operation-explicit). Eye movement metrics (first click time, gaze points, hotspot map, gaze path), task load and satisfaction were collected through eye tracking system and subjective ratings. The results indicate that task type significantly influences user search behavior and efficiency. In operation-explicit tasks, users reduced searching time on page, and perceived higher satisfaction and task load. Operation-fuzzy task results in random search behavior and complex eye movement paths. Interaction modality also significantly influences searching efficiency. Voice modality results in a significantly higher number of page switches. Touch modality performed better in operation-fuzzy task, followed by eye control modality. This study reveals the relationship between user search behavior and visual attention, providing insights for interaction system design.