Abstract: In order to research the dynamics response of the long-span bridge under the blasting seismic wave, the Suancigou bridge nearby Heidaigou open-cast coal mine was taken as an example and a numerical model was developed for its single pier. Through the finite element method software ANSYS and LS-DYNA , the modal and dynamic time history of the pier were simulated. The results show that while the dominant frequency range of input blasting seismic wave is 2~5 Hz, the response of 2 Hz is the most obvious. The pier damage occurs while the peak velocity reaches the 8.71 cm/s, and the damage area is located on the bottom of the pier wall. The safety ratio distance of the bridge pier is 5.79.