Abstract: Comparison specimens of brazed structures such as honeycomb structure, panel structure and radar array antenna surface structure used for ultrasonic C-scan test were designed and fabricated. A series of presetting artificial defects methods were tested by ultrasonic C-scan inspection to select the proper comparison specimen for specific brazed structure. The result shows that the proper comparison specimen for panel brazed structure should be made by drilling a through hole before brazing. The best way to make a comparison specimen for brazed structure of honeycomb should be as follows: the curing agent was injected to the honeycomb after brazing, machining a flat bottom hole and then using heating or chemical method to remove curing agent. For the antenna surface brazed structure comparison specimen, the best way to make it is milling strip defects in lower plate near the rib plate position after brazing.