To screen a strain of GABA-producing lactic acid bacteria suitable for Aronia melanocarpa juice fermentation and optimize the fermentation process, this study employed response surface methodology (RSM) coupled with an artificial neural network-genetic algorithm (ANN-GA) model and evaluated the effect of fermentation on flavor. Six GABA-producing strains were initially screened using thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). The optimal strain for Aronia melanocarpa juice fermentation was determined through re-screening in the juice matrix combined with physiological characterization. Subsequently, the coupled RSM-ANN-GA model was used to optimize the fermentation process for GABA enrichment, and the impact of fermentation on flavor was assessed using sensory evaluation and electronic tongue analysis. Results showed that Levilactobacillus brevis Lj16 was identified as the most suitable strain, achieving a GABA yield of 2.07 mg/mL in Aronia melanocarpa juice, significantly higher than other strains (P< 0.05). Physiological characterization revealed that Lj16 exhibited a survival rate of 65.79% after 4 h of exposure to pH 2.5, a high glutamate decarboxylase (GAD) activity of 2.02±0.01 U/mL, and mild acid production (final pH 5.0), which favors sustained GAD activity. Using this strain, the optimal fermentation conditions determined by the coupled RSM-ANN-GA model were: L-monosodium glutamate 2.30%, yeast extract 2.40%, fermentation temperature 36.5 °C, and fermentation time 120 h. Under these conditions, the GABA yield reached 8.77±0.16 mg/mL. Sensory evaluation and electronic tongue analysis demonstrated that the fermented juice exhibited significantly reduced astringency and sourness, along with markedly improved flavor harmony. This study successfully screened a lactic acid bacterium suitable for GABA enrichment in Aronia melanocarpa juice fermentation. The coupled RSM-ANN-GA model effectively optimized the fermentation process, enhancing GABA accumulation while improving product flavor, providing both a valuable microbial resource and a process foundation for developing high-GABA functional fermented beverages.