A method for quickly identify damaged building damage by earthquake based on multi-structural elements includes such step as reconstructing top hats of multi-structural elements, reconstructing multi-directional top hats, constructing differential morphological section, averaging that differential morphological section to construct building morphological features, post-processing images and extracting damaged building information after earthquake. As that method of the invention can extract the damage buildings damage by the earthquake only through the single-phase image after the earthquake,Single-phase seismic damage image can identify the damaged buildings in a short time with high precision, The correct selection of structural elements in the operation of differential morphology section improves the effect and quality of target recognition, which not only improves the extraction precision, but also simplifies the operation, and the processing speed is fast, which is not affected by the subjectivity of the operator, and solves the problems existing in the object-oriented method.