Abstract: A distributed multi-channel ultrasonic flaw detection system was developed. The key components of embedded systems hardware was Field Programmable Gate Array. The use of System on Programmable Chip accomplished real-time control, and analog and digital integrated circuits constitute ultrasonic module with open architecture network distribution and without the restrictions on the numbers of computer card. With fast and accurate flaw detection and on-site anti-interference ability, the system channels could be as high as many hundreds. The system was characteristic of the function of modular, free portfolio, simple connection and was functional and reliable.