Abstract: With the composite structure and its parts being widely used in aerospace, higher requirement for the nondestructive testing technology has been put forward. Different sizes of artificial defects were buried in glued buried structure,laminated structure, and honeycomb sandwich structure in the carbon fiber reinforced resin matrix composite material test blocks, and these test blocks were tested with ultrasonic and the way how to set the parameters to detect embedded defect effectively was discussed. The results showed that through properly selecting the appropriate detection equipment and testing parameters, all the embedded artificial defects could all be detected.