Numerical models for single-layer Kiewitt-8 reticulated domes with the span of 60 m and cylinder impactors were established by the ANSYS/LS-DYNA program and a series of numerical simulations were carried out. Four failure modes for the reticulated domes were put forward according as the displacement and plastic deformation. The whole failure process was divided into three steps including energy applying, energy loss and energy transfer, energy consumption, by the dynamic response characteristics of each step. Failure mechanisms of the reticulated domes were explained at the two aspects of energy transfer and failure types for members in impact zones. Energy analysis displays that the left energy (Elf) is the main factor to decide the final dynamic response and failure mode, but Elf is the initial impact energy eliminated penetrating loss by the impactor and local breakage loss by members in the impact zone. Analysis for failure types of members indicates that failure of members may lag by contrast the end of impact load, and failure types of members decide the ability of energy transfer. When remembers undergo tension failure, intensities of members are made full use of, the most energy is transferred, the left energy is more, and the whole reticulated dome experiences severe breakage. Moreover, there is a good consistent relationship among failure types of members, failure modes of the reticulated dome and left energy.