For this research, electroencephalography (EEG) was analyzed to investigate the perception ability of the brain for moving objects at different speeds. In this experiment, total six kinds of videos regarding license plates were created, moving at distinct speed of 0.26 m/s, 0.36 m/s, 0.46 m/s, 0.56 m/s, 0.66 m/s, and 0.76 m/s, respectively. In the semantic priming paradigm, the N400 effect was analyzed for each speed. The ERP results demonstrated that the N400 amplitude gradually reduced with increasing speed. At the three lower speeds, N400 was evoked evidently and mainly distributed in the centro-posterior region. At the three higher speeds, no significant N400 effect was found. The results concluded that the perception ability of the brain declined with the acceleration of the object’s moving speed and that the brain recognized the detailed information of the moving object when its speed was lower than 0.46 m/s.