Abstract: The section damage index of a structural component is defined, and based on the incremental dynamic analysis (IDA) method, the failure modes of a structure due to earthquakes are classified to further statistically calculate the mean values of component section damage under different failure modes. A probability-based seismic failure-modes identification method is proposed to establish the structural failure probability formula under different failure modes. As a numerical example, a 20-story benchmark steel frame structure is analyzed based on OpenSees platform. The results indicate that:structural failure modes can be reasonably classified according to the damage states of key floors, the effects of the component section damage on structural failure modes can be well reflected by the introduction of component importance coefficients, and the occurrence probability of different failure modes can be effectively distinguished by the probability-based seismic failure modes identification method.