Abstract: To study the nutritional composition and flavor characteristic substances of fresh Amomum tsao-ko, gas chromatography-mass spectrometry (GC-MS), amino acid autoanalyzer, and gas chromatography-sniffing were used to analyze and identify the nutritional composition and volatile flavor substances of fresh Amomum tsao-ko. The results showed that fresh Amomum tsao-ko contained the highest moisture content of 70.61%, crude fat of 2.35%, crude protein of 2.76%, and total ash of 5.94%. A total of 30 fatty acids were detected in fresh Amomum tsao-ko, with contents ranging from 0.10 to 3.45 mg/mL, among which, 12 saturated fatty acids accounted for 57.99% of the total amount, and 18 unsaturated fatty acids accounted for 47.23% of the total amount. Among the nine amino acids detected, lysine was the highest and valine was the lowest. By comparing the aroma characteristics, mass spectra, and retention indices with those of the standards, 46 volatile flavor substances were identified from them, and citral, (Z)-3,7-dimethyl-2,6-octadienal, (E)-3,7-dimethyl-2,6-octadienal, trans-2-dodecenal, and trans-2-octadienal were found to be in high contents. The key aroma components of fresh Amomum tsao-ko were identified as nine substances, namely, trans-2-dodecenal, (E,Z)-2,4-decadienal, trans-2-octenal, n-octanal, 4-isopropyltoluene, (Z)-3,7-dimethyl-2,6-octadienal, (E)-3,7-dimethyl-2,6-octadienal, citral, and eucalyptol, based on the intensity value of the aroma and its odor activity value. The results would provide a theoretical basis for the drying and processing of fresh Amomum tsao-ko and product development.