In this study, we investigated whether working on object tracking tasks which induces mentalfatiguehad a subsequent differential effect on globaland local processing.Twelve rifle shooters under mentalfatigue performed a globaland local processing task. Reaction time, number of errors, and event-related brain potentials were recorded. The following results are concluded. (1) Objecttracking tasks can effectively induce mentalfatigue of twelve rifle shooters. (2)Compared to local processing, fatigued shooters showed faster and more accurate performance on global processing. (3) Fatigued shooters were unable to inhibit automatic shifting ofattention to local stimuli on globalprocessing task, implied by a larger negativity in the frontal-central N2/P3 for local compared to global stimuli. (4) Fatigued shootersshowed compromised local processing and disturbed automatic shifting ofattention to local stimuli on localprocessing task. Thelarger negativity of frontal-central N2/P3 for local stimuli could not be found. These results indicate that mentalfatigue selectively influencesglobaland local processing. Compared to automatic global processing, local processing is more likely to be disturbed by mental fatigue in top-down style.