The change regulation of vigilance based on functional near-infrared spectroscopy (fNIRS) is studied. During the experiment, the hemodynamics signals of 12 participants including oxygenated hemoglobin (HbO) and deoxygenated hemoglobin (Hb) are recorded through 10 channels fNIRS technology, and the behavior data of the participants are simultaneously recorded. The results indicate that vigilance of the participants can be labeled as three levels: the first 30 min is high vigilance level, the middle 30 min is general vigilance level, and the last 30 min is low vigilance level. Additionally, the results indicate that channel 2 on the left side and channel 9, channel 8, channel 7 and channel 6 on the right side of prefrontal have better sensitivity to vigilance change. Under support vector machine recognition model, the average accuracy over the 12 participants of three-level-classification results is 76.9%. The experimental results confirm the feasibility of fNIRS in the evaluation of vigilance, and point out the specific locations of the sensitive brain region, which provides a new way for real-time vigilance monitoring.