In order to solve the problem of the recognition of manufacturing features in engineering drawings based on geometrical CAD data modal, semantic information in 2D drawings is first analyzed. Based on the intelligent pattern recognition theory, the semantics and basic entities are regarded as pattern primitives and the relationships between entities as operation rules. Pattern classes are built based on syntax structure. Recognition can be accomplished through extracting, analyzing syntax and matching. A feature recognition system is developed based on AutoCAD with ARX technology.