Objective To investigate the effect of heat moist treatment on the γ-aminobutyric acid (GABA) content of different varieties of red kidney beans and to screen out the red kidney bean varieties with the strongest GABA accumulation capacity. At the same time, the changes in phenolic content and antioxidant activity of red kidney beans after heat moist treatment are investigated.Methods This paper determines the GABA content in red kidney beans before and after heat moist treatment by high performance liquid chromatography (HPLC) and conducts correlation analyses of GABA accumulation with free amino acid content and GABA key metabolic enzyme activities in red kidney beans.Results The GABA content in 12 red kidney beans is significantly enhanced to different degrees after heat moist treatment, with an average increase of 34.91-fold. Among them, the highest GABA content (108.25 mg/100 g) is found in Pinjin Yun 3 and the lowest GABA content (64.25 mg/100 g) in Pinjin Yun 1. In terms of GABA shunt, the glutamic acid content in red kidney beans is significantly lower (P<0.05) and the activity of glutamic acid decarboxylase (GAD) is significantly higher (P<0.05), both of which are significantly correlated (P<0.05) with the GABA accumulation. Regarding the polyamine degradation pathway, the activities of polyamine oxidase (PAO) and diamine oxidase (DAO) are significantly elevated (P<0.05), but there is no significant correlation with GABA accumulation.Conclusion The GABA accumulation in red kidney beans under heat moist treatment is mainly attributed to the GABA shunt. In addition, heat moist treatment significantly increases the total phenolic content and antioxidant activity of red kidney beans but slightly decreases the flavonoids content.