The invention provides a fault polygonal processing method suitable for the correction of a section abnormal value of paleotopography recovery, and the method comprises the steps: partitioning an irregular fault polygon which is outputted by an explanation system and has assigned upper and lower layer positions into two or more convex polygons; combining the obtained convex polygons at the assigned upper and lower layer positions through the comparison of areas, distances, and extending directions, and giving a unified identification for describing the polygons of the same fault; combining two obtained convex polygons with the same identification, and obtaining a new convex polygon which is used for describing the range of section data exception caused by the same fault. The method can carry out processing of section data on the basis of strictly defining the distribution range of the abnormal value, thereby improving the correction precision of the abnormal value of a section, and improving the recovery precision of paleotopography.