<p>Chronic heroin addiction induces severe physiological dependence and systematically impairs the neural mechanisms underlying basic cognitive functions. However, the specific effects of opioids on divergent thinking—a higher-order cognitive function—and its neural basis remain underexplored. This study recruited individuals with chronic heroin use disorder (HUD, <i>n</i> = 38) and healthy controls (HC, <i>n</i> = 35) to record neural activity during divergent thinking tasks (Alternative Uses Test, AUT) using electroencephalography (EEG). Source-space analysis quantified power spectral density (PSD) in brain regions, complemented by functional connectivity analysis using weighted phase lag index (wPLI) from selected seed regions. Machine learning assessed the utility of connectivity metrics as cognitive impairment markers. Source-space analysis revealed that compared to the HC group, the HUD group exhibited increased alpha-band power in the left precuneus (L.PCUN) and left superior parietal lobule (L.SPL) and beta-band power in the right superior parietal lobule (R.SPL). Functional connectivity analysis revealed weakened cross-network coupling between the default mode network (DMN) and frontoparietal control network (FPN), with reduced alpha connectivity between the right superior frontal gyrus (R.SFG) and L.PCUN correlating with impaired divergent thinking. Machine learning confirmed this metrics as effective neurobiological markers (AUC = 0.772, accuracy = 0.767) of cognitive impairment in heroin addiction. The findings indicate that abnormal local oscillatory activity and disrupted network integration impair the dynamic “generation-evaluation” loop of divergent thinking, constituting a compensatory pathological mechanism. This study provides neural evidence linking opioid addiction to creativity deficits and supports precision interventions targeting cognitive dysfunction in addiction.</p>