This study aimed to evaluate the diagnostic value of high-frequency ultrasound examination for carpal tunnel syndrome (CTS). A total of 63 wrists from 45 patients diagnosed with CTS were selected as the study group, and 43 asymptomatic wrists of 40 cases were included as the normal control group. Parameters such as the transverse diameter, vertical diameter, cross-sectional area (CSA), and flattening rate (FR) of the carpal tunnel radioulnar joint, postular bone, and median nerve in the hamate bone hook plane were measured, and the differences between the two groups were compared. The median nerve CSA in the postular bone plate was significantly greater in the study group than in the normal control group (0.17±0.05 vs. 0.09±0.02, P<0.01), and the FR at the hook of the hamate was significantly higher in the study group (3.52±0.86 vs. 3.21±0.26, P<0.01). Our results suggest that ultrasonography can effectively provide dynamic real-time images of the wrist in addition to being painless, non-invasive, and associated with relatively low costs. Based on our findings, we believe that ultrasonography is an effective examination method for CTS. When the threshold of the median nerve CSA in the postular bone plate was set as 10 mm(2), the diagnostic sensitivity and specificity were 92% and 86%, respectively. Therefore, the median nerve CSA may represent a good clinical indicator of CTS.