Abstract: A single event upset (SEU) effect test method using a beat frequency to test the high-speed analog-to-digital converter (AD) with a high frequency dynamic input was proposed. The test method was demonstrated on a 8 bit 3 GPSP AD using different types and energy of heavy ions with a SEU effect test system. By the analysis of the test figure and the error data, the parameter of device can be calculated, providing basis and guidance for high-speed AD’s radiation harden design.