Abstract: In order to test the repair quality of composite materials and detect the defects such as repair area lamination, three kinds of simulated repair specimens with different processes including high temperature curing prepreg (PL2+PA2) repair, medium temperature curing prepreg (PL1+PA1) repair, wet layup (WF1+WR1) repair were made. Then, the ultrasonic testing was used to detect and evaluate the repair area. The A-scan, B-scan and C-scan imaging detection of the CFRP laminate repair area was carried out with a normal probe, a waterimmersion point focusing probe and a roller probe. Finally, the tensile failure test of the composite plate was carried out. The experimental results showed that ultrasonic testing can be used to detect the delamination defects in the repair area of composite materials; The area repaired by wet layup repair (WF1+WR1) process had the smallest sound energy absorption during ultrasonic testing, and its acoustic performance was closer to that of raw materials, which is conducive to ultrasonic testing; The material strength recovery was better when the medium temperature curing prepreg repair (PL1+PA1) process was used and the small scarfing slope was used.