Abstract Objectives This study aimed to investigate the effects of brief mindfulness meditation on emotion regulation and its underlying brain functional network mechanisms in college students using functional near-infrared spectroscopy (fNIRS), thereby providing neuroscientific evidence for mindfulness-based interventions targeting emotional health. Method A total of 59 college students were randomly assigned to either a brief mindfulness meditation group (n = 29) or a control group (n = 30). Participants in the mindfulness group completed a 15-min mindfulness breathing intervention, whereas participants in the control group received safety education. Before and after the intervention, all participants performed an emotion regulation task involving negative viewing and cognitive reappraisal conditions. Changes in oxygenated hemoglobin (Oxy-Hb) concentration were recorded using a 40-channel fNIRS system across eight regions of interest, including the left dorsolateral prefrontal cortex (L-dlPFC), right dorsolateral prefrontal cortex (R-dlPFC), left frontopolar area (L-FPA), right frontopolar area (R-FPA), left premotor cortex (L-PMC), right premotor cortex (R-PMC), left primary somatosensory cortex (L-S1), and right primary somatosensory cortex (R-S1). Brain functional connectivity was constructed based on phase-locking value (PLV), and graph-theoretical metrics were subsequently calculated to characterize topological properties of the functional network. Results Behavioral results indicated that, compared with the control group, participants in the brief mindfulness meditation group exhibited significantly lower emotional valence ratings during the negative viewing condition (p < 0.001). Functional connectivity analyses revealed significantly increased connectivity between the L-dlPFC and L-FPA, L-dlPFC and R-PMC, and L-dlPFC and L-PMC following the mindfulness intervention ( p < 0.05). Furthermore, graph-theoretical analyses demonstrated significantly increased global efficiency, as well as enhanced local efficiency and clustering coefficient of the L-dlPFC in the mindfulness group ( p < 0.05). Conclusions Brief mindfulness meditation may effectively enhance functional integration within large-scale brain networks and improve neural information-processing efficiency in college students. These findings provide important neurophysiological evidence supporting the beneficial effects of mindfulness interventions on emotion regulation.