Abstract: The defects both in the edge and central areas of the casting products were detected by using ultrasonic testing. Based on the comparative analysis on the echo waveforms of different defects and on the dissection validation of a defect part, it was found that, while detecting the casting parts from different directions and using different types of probes, it was necessary to comprehensively analyze and evaluate the defect through the combination of casting process, the defect characteristics, the defect waveforms and the bottom wave. All the above mentioned measures can raise the inspection accuracy and reliability and provide bases for improving the manage level and product quality.