Background <p>Alcohol-related cues are a critical factor in relapse among individuals with alcohol use disorder (AUD), yet their neuroelectrophysiological mechanisms at the brain network level remain unclear. This study aims to investigate alterations in functional connectivity and topological properties of brain networks in AUD patients during alcohol cue processing.</p> Methods <p>A three-stimulus oddball paradigm with alcohol-related images was used. After rigorous EEG quality control, 16 AUD patients and 16 matched healthy controls were included in the final analysis. Source-level phase locking value (PLV) was used to construct functional connectivity matrices, followed by graph-theoretical analysis of network topology. Correlations with drinking characteristics and clinical scale scores were also examined.</p> Results <p>During alcohol cue processing, the AUD group exhibited reduced delta-band (1–4&#xa0;Hz) functional connectivity, primarily involving the default mode, frontoparietal, and cingulo-opercular networks (<i>p</i> = 0.034). In the theta band (4–8&#xa0;Hz), the shortest path length increased (<i>p</i> = 0.01, <i>q</i> = 0.04, Cohen’s <i>d</i> = 0.96), with significantly decreased nodal centrality in the right prefrontal cortex, left posterior insula, and left basal ganglia, and increased centrality in the left parietal, bilateral occipital, and right mid-insula regions (all <i>p</i> &lt; 0.01, <i>q</i> &lt; 0.05). Centrality metrics in several key brain regions were significantly correlated with drinking behaviors and clinical scale scores.</p> Conclusions <p>AUD patients exhibit impaired delta-band network integration, reduced theta-band information transfer efficiency, and disrupted nodal centrality during alcohol cue processing, indicating abnormal neural mechanisms underlying cue-reactivity.</p> Trial registration <p>This study was registered in the Chinese Clinical Trial Registry (ChiCTR2300076251) on September 28, 2023. Recruitment began on October 1, 2023.</p>