γ-Aminobutyric acid (GABA) has several well-known physiological functions including antihypertension and antidepression. In this research, we focus on the antidepressant effects of oral administration of GABA-rich Monascus-fermented product in depression animal model (forced swimming test, FST) by Sprague-Dawley rats, and try to find its possible mechanism in the brain monoamine system. GABA and the Monascus-fermented product (MFP) significantly decreased the duration of immobility time in a short-term test. In a long-term test, the antidepressant-like effect of MFP was better than that of GABA at the same dosage (2.6 mg/kg), and the efficacy of MFP was similar to that of fluoxetine. Moreover, GABA might recover the level of monoamines norepinephrine, dopamine (DA), and 5-hydroxytryptamine (5-HT) in hippocampus and normalize the turnover ratio of 5-HT and DA in hippocampus and amygdala. In addition to the functions of GABA, the MFP has more potential in decreasing the turnover ratio of DA in the frontal cortex and striatum to improve depressive symptoms.