Abstract: Objective: To investigate the effects of acute exercise on directed forgetting of negative information, as well as the role of the prefrontal cortex in this process. Methods: Fifty-six undergraduate students were randomly assigned to an exercise group or a control group, the exercise group conducted an intervention program of high-intensity interval exercise. Negative and neutral words served as learning materials, and a short-list directed forgetting task was adopted. During the learning phase, fNIRS was used to synchronously collect oxygenation level data of the prefrontal cortex during material presentation and instruction execution. Results: Behavioral results showed that the exercise group had a higher correct number of free recall and a stronger directed forgetting effect for neutral words than that of negative words, but no difference was observed in the control group. fNIRS results demonstrated that during instruction execution in the learning phase, acute exercise increased oxygenated hemoglobin concentration in the bilateral dorsolateral prefrontal cortex, with an interaction effect between group and lexical type observed in the left dorsolateral and left ventrolateral prefrontal cortex. Specifically, the exercise group exhibited higher oxygenated hemoglobin activation levels than the control group when executing instructions involving negative words. Correlation analysis between behavioral performance and fNIRS data revealed that the bilateral dorsolateral prefrontal cortex activation in the exercise group was negatively correlated with the number of correct recall responses under instruction forgetting conditions, whereas the control group showed a positive correlation between prefrontal cortex activation and memory performance. Conclusion: Acute exercise remodels the association pattern between prefrontal cortex activation and the execution of directed forgetting commands, shifting its function from enhanced encoding to optimized inhibition. Thus, a more efficient inhibitory mechanism is established to reduce the processing priority of negative information and facilitate the execution of directed forgetting commands, thereby validating the pivotal role of prefrontal cortex functional optimization in exercise-induced directed forgetting.