1. An apparatus for logically processing a composite graph in a foi matted document, comprising: a composite graph block extraction unit, configured to extract a composite graph block in the formatted document; a document parsing unit, configured to parse the formatted document to obtain a text element included therein; a cutline element extraction unit, configured to extract a cutline element from the text element; a correlativity detection unit, configured to detect correlativity between the composite graph block and the cutline element; and a correlativity storage unit, configured to store the detected correlativity.