By exerting the 10/350 μs current shock wave to class Ⅱ test SPDs, which have different nominal discharge currents, by using impulse current generator to observe the relation of the classⅡtest SPD’s nominal discharge current and impulse current, the feasibility of class Ⅱ test SPD discharging impulse current is studied. The experiment shows that in the experiment, four different models of the class Ⅱ test SPDs can pass the impulse current of 0075, 0075, 01, 0125 times of the nominal discharge current, and the average theoretical deviation is-625%, which is consistent with the theoretical research; it is feasible to use the class Ⅱtest SPD to discharge the impulse current, but there is big difference between different brands and models for the ratio of the impulse current to the nominal discharge current. Due to the limitations of the actual products in the market, in practice, the use of the class Ⅱ test SPD instead of the class Ⅰ test SPD as the first stage of SPD is feasible.