Objective To compare the value of B-flow and color dopplor flow image(CDFI) in preoperative localization of perforator flap. Methods Of 30 patients who underwent flap transplantation in our hospital, CDFI and B-flow were used to detect the number of perforator vessels in the donor site of the flap before surgery. The times taken using CDFI and B-flow to detect perforating vessels were recorded before surgery, and the differences between the two modes were compared. The differences between CDFI and B-flow used to detect the number of perforator vessels in the flap donor area were compared; According to the inner diameter, path, peak systolic velocity (PSV), resistance index (RI) and other indicators of the perforator vessels, the optimal perforator vessels were selected. CDFI and B-flow were used to locate and mark the optimal perforator vessel point for the perforator flap before surgery. During the operation, the distance to the actual puncture point was measured separately and counted as the AC value and BC value to compare the difference between AC and BC. Results ① B-flow takes less time than CDFI (t=12.721, P<0.05).②B-flow was better than CDFI in detecting perforator vessels (Z =-3.528,P<0.05).③The BC value was lower than the AC value (t=3.328, P <0.05).