A logic process apparatus for composite graphs in a fixed layout document is provided in this invention. The apparatus includes a composite graph block extraction unit, for extracting composite graph blocks from the fixed layout document, a document parsing unit, for parsing the fixed layout document to obtain text primitives contained therein, a legend primitive extraction unit, for extracting legend primitives from the text primitives, a correlation detection unit, for detecting correlations between the composite graph blocks and the legend primitives, and a correlation storage unit, for storing the detected correlations. A logic process method for composite graphs in a fixed layout document is also provided.