While the cognitive benefits of aerobic fitness have been widely investigated, current findings in young adults remain unclear. Specifically, little is known about how these effects are reflected in the time–frequency domain. This study thus assessed the relationship between aerobic fitness and neural oscillations during visuo-spatial attention. A between-subjects design that included 20 participants with higher aerobic fitness (age = 21.95 ± 2.24 years; VO2max = 58.98 ± 6.94 ml/kg/min) and 20 age- and gender-matched lower aerobic fitness participants (age = 23.25 ± 2.07 years; VO2max = 35.87 ± 3.41 ml/kg/min) was used to examine the fitness-related differences in performance and neuroelectric indexes during a Posner visuo-spatial attention paradigm. The results demonstrated that high-fitness participants, in comparison with their low-fitness counterparts, showed faster reaction times as well as greater modulation of oscillatory theta and beta power during target processing, regardless of cue types. Moreover, the neurocognitive correlation showed that higher theta power was related to better task performance. Collectively, these findings suggest that aerobic fitness is associated with general enhanced attentional control in relation to visuo-spatial processing, as evidenced through greater motor preparation and in particular the up-regulation of attentional processing in healthy young adults. The present study may contribute to current knowledge by revealing the relationship between aerobic fitness and modulation of brain oscillations.