Abstract: Aiming to solve problems faced by existing calibration devices for ultrasonic testing systems, such as narrow frequency band, poor portability and inconvenient on-site operation, analysis and research on the principles, methods, and standards of calibration techniques for ultrasonic testing systems were then undertaken. As a result, field programmable gates (FPGA) were used to forms a sinusoidal signal generator with DDS (direct digital frequency synthesis) technology, and by integrating a digital attenuator, an ultrasonic detection system with a wider frequency range, higher frequency accuracy, smaller volume, lighter weight, and higher integration has been developed. Through comparative research with the calibration results of similar domestic equipment, the calibration results of the new calibration device fully meet the requirements of relevant measurement regulations, calibration specifications and standards, which are comparable to the calibration level of similar domestic equipment, and are more suitable for large-scale ultrasonic inspection systems on industrial sites calibration.