The present study used the event-related potentials to investigate the effect of task-irrelevant, high-approach versus low-approach motivational positive affect on proactive and reactive control, and their neural mechanisms. A cue stimulus and a probe stimulus were presented successively in each trial. Participants were required to maintain the information of the cue and respond to the probe. The results showed that high-approach positive affect reduced the amplitudes of P3b after the cue of low frequency and enlarged the amplitudes of contingent negative variation before all the probes. Conversely, low-approach motivational positive affect improved the amplitude of P3a after the probe in some trials. These findings demonstrated that high (compared with the low)-approach motivational positive affect improved proactive control and influenced the early stage of the cognitive control process. Low (relative to high)-approach motivational positive affect facilitated reactive control and influenced the late process stage of cognitive control.