Abstract: Based on the sound velocity measurement theory, using RSM-SY5 intelligent sound wave apparatus, damage of the surrounding rock under blasting load in a strip iron mine was studied by in-situ tests on sound waves. It is shown that the damage range of the surrounding rock caused by blasting excavation is 7 m in this strip iron mine, and the damage degree decreases with the increase of the distance of the surrounding rock from the blasting center. The sound velocity in rock mass decreases gradually with the increase of the blasting times and it means that the repeated blasting loads present a cumulative damage effect to rock mass. The cumulative damage is not the simple addition of the damage induced by the repeated single blasting loads, and takes on a non-linear increase. And the shorter the distance of the rock mass from the blasting center is, the more distinct the cumulative damage effect is.