At present, the research on the radiation-harden ability is the hot spot in the field of aerospace devices. In the paper, one commercial D flip-flop chain and one radiation-harden D flip-flop chain are chosen to be tested on the five conditions of different work frequency in the range of 100k~100M. The test would help us to study the frequency effect on SEE. The result shows that when the work frequency increases 103 times, the upset threshold of commercial D flip-flop chain is almost unchanged, but the saturation cross section of the single event upset (SEU) increases about 7.13 times. Compared with radiation-harden D flip-flop chain, the reinforced chain has higher upset threshold, lower upset saturation cross section, and the saturation cross section increases about 3.71 times when the work frequency increases 103 times.