The aim of this study was to discuss the diagnostic value of dual-energy computed tomography (DECT) in patients with gout during different disease phases. Two hundred twenty-one patients (136 with gout and 85 with other arthritic diseases) were recruited to the study. Arthrosis pain was evaluated in all patients by DECT scans. We calculated the sensitivity and specificity of DECT for the diagnosis of gout, including the first onset period, less than 24 months period, and more than 24 months period. We then investigated the related risk factors of urate crystals volume in the foot. The diagnostic sensitivity of DECT in the first onset, less than 24 months, and more than 24 months groups was 35.71, 61.54, and 92.86%, respectively. The overall sensitivity and specificity values were 80.88 and 88.24%, respectively. The multilinear regression analysis showed that longer disease duration (P = 0.001) and higher serum uric acid (SUA) (P = 0.001) were the two important predictive factors of the monosodium urate (MSU) crystal volume in the foot. DECT provides good diagnostic accuracy for detection of MSU crystal deposits in gout patients. However, DECT has limited diagnostic sensitivity for short-term gout patients, especially for the first onset patients. Longer disease duration and higher SUA were predictive factors of MSU crystal volume.