Abstract: Great discoveries have been achieved successively in the buried-hill reservoirs of metamorphic rocks in Bohai area, but there are lack of targeted methods to study weathering crust of metamorphic rocks. Taking the weathering crust of metamorphic rocks in Bozhong X structure in the Bohai Sea as the study object, and based on thin section observation, logging data, element mud log data, characteristic element extraction and clustering analysis, a set of quantitatively comprehensive evaluation methods is established for weathering crust, which can clearly identify and classify vertical structures of metamorphic rock weathering crust. The method has been applied in the newly drilled Well B and 4 zones are classified from top to bottom, i.e., weathering crush zone, strongly weathering fracture zone, weak weathering fracture zone and unweathering fracture zone, which provides references for the exploration in the area