The invention relates to an unconformity stratum denudation amount recovery method and belongs to the field of geological structure evolution research and oil gas resource quantitative evaluation. According to the invention, by use of sound wave time difference data corresponding to a mudstone well segment of each single well in a target area with a denudation amount, logarithmic relations between unconformity upper and lower stratum mudstone well segment embedment depths and sound wave time differences are established, compacting features of old strata below an unconformity before denudation are determined, compacting trends of stratum mudstones below the unconformity are extended upwards to a paleo-ground surface, and thus a stratum denudation amount at the unconformity is determined. According to the invention, the recovered denudation amount has a good positive correlation relation with paleotopography, the recovery precision is high, the rationality is high, and therefore, the applicability is wide.