Abstract: To realize the overall evaluation of brazed joint quality, ensure the connection quality of finished brazed workpieces and verify the brazing process, and avoid the destructive disadvantages of traditional physical testing methods, the water immersion ultrasonic testing method was used to analyze the C-scan image, so as to realize the nondestructive, efficient and automatic evaluation of brazed joint quality. By selecting the probe, adjusting the water distance, setting the scanning mode, and using the corresponding reference block to adjust the scanning sensitivity, the test parameters were determined. The results showed that the ultrasonic C-scan results could directly characterize the quality of the brazed layer. The metallographic and EDS analysis of the areas with different echo heights verified the corresponding state of the brazed layer.At the same time, for planar workpieces, tubular workpieces and multilayer brazed workpieces, the joint state and internal defect position of brazed joint could be reflected efficiently, intuitively and comprehensively. Using the area statistical function of the software, the brazing rate was calculated according to the formula and the non-destructive and quantitative evaluation of brazing quality was realized.