The content of total phenolics, DPPH-free radical scavenging effect, total antioxidant activities, and nutritional properties of Thua Nao (TN), a Thai traditional fermented soybean, collected from four ethnics’ conventional methods in Northern Thailand were investigated. In general, the samples contained 6.18–7.04% moisture, 3.24–3.78% ash, 47.43-49.50% protein, and 4.16–4.88% fat. The total phenolic contents of methanol extracts of the various TN, varying on the source of sampling, range between 31.45 and 39.54 (mg/L of gallic acid). For antioxidant activity, the IC50 values as determined by the DPPH method ranged from 22.52 to 2.81 mg/mL of sample extract. There may be variations between these properties. Because of the variety of soybeans, the fermentation method, and starter microorganism species. Our study provides detailed information regarding the nutritive quality of TN. The commodity tends to be a decent source of protein-based on protein content and a potent in the antioxidant diet with high phytochemical antioxidant content and powerful antioxidant activity.