Objective: To evaluate the efficacy of color Doppler ultrasound multi-parameter comprehensive diagnosis of carpal tunnel syndrome (CTS).Methods: Two-dimensional ultrasonography was performed to observe the shape, internal echo and thickness of the the median nerve in carpal tunnel level and above. The cross-sectional area (CSA1) at the entrance level of the carpal tunnel and the cross-sectional area (CSA2) at the level of Rotating anterior muscle of the median nerve (MN) was further measured, and then compared area difference (ΔCSA=CSA1-CSA2) and wrist-forearm area ratio (WFR=CSA1/CSA2); CDFI was used to observe the flow signal of the median nerve ; exercise test was used to measure the move deformation coefficient of the median nerve (MDC) and the compression coefficient (CDC) of the median nerve during compression at the entrance level of the tube.Results: 1,ultrasound images feature of 28 CTS: Edema and thickening, echo reduction, parallel line echo and reticular structure blurred or disappeared of MN; 2, In this study, the CSA cut-off value was 10.40 mm2, and the sensitivity (82.1%) and specificity (86.7%) were higher in diagnostic CTS. The cut-off values of ΔCSA and WFR for diagnosis of CTS were 5.15 mm and 2.55, respectively. The sensitivity of ΔCSA for the diagnosis of CTS was higher, and the sensitivity (75.0%) and specificity (73.3%) for WTS diagnosis of CTS. The median nerve motor deformation coefficient (MDC) and compression deformation coefficient (CDC) cutoff values of 1.45 and 0.95 respectively in diagnose of CTS , and their sensitivity to diagnosis of CTS is high and the specificity is not high;3,CSA+CDFI+exercise test diagnosis CTS has higher sensitivity and specificity. Conclusion: Color Doppler multi-parameter combination can improve the efficacy of diagnosis of carpal tunnel syndrome.