In order to provide basis for seismic research of the tower of long-span suspension bridge,the longitudinal damage characteristics of the tower of long-span suspension bridge under earthquake action is explored. A finite element model is established used ADINA by taking a long-span suspension bridge as the example and the development characteristics of plastic damage of the tower is observed by 20 earthquake excitations with increasing intensity in the longitudinal direction. It is found that with the increase of earthquake intensity,the development of the plastic damage at the bottom of the tower and in the middle of the tower bottom is synergistic. However,the rate of development of the plastic damage at the bottom of the tower is far greater than that in the middle of the tower,which leads to the low level plastic damage degree in the middle of the tower when the final section fails at the bottom of the tower.