In order to investigate the damage models and failure mechanism of the outer concrete tank of the liquefied natural gas (LNG) storage tank under impact loading, the finite element (FE) model of the outer concrete tank of 160,000 m3 LNG storage tank for an actual LNG project and a cylindrical impactor are established based on ANSYS/LSDYNA FE analysis software platform. Through the result comparison of the numerical simulation and an impact perforation test of reinforced concrete slabs subjected to projectile with high speed, the accuracy of the numerical simulation method and material model proposed from this paper are verified. The dynamic response of the concrete dome for LNG outer concrete tank structures under impact loading is studied. Based on response rules and failure phenomena of the dome for LNG outer concrete storage tank subject to impact loading, three damage modes are defined, and the failure mechanism for each mode is revealed from the view point of energy.