The invention discloses a vertical graph recognition method for converting a building drawing into a three-dimensional BIM model, and the method comprises the following steps: a, obtaining a target graph layer of the CAD building drawing, and obtaining a wall graph layer, a door and window graph layer, an elevation graph layer, an axis symbol graph layer, and an axis network graph layer; b, performing direction identification, elevation symbol identification and story height acquisition on each vertical drawing of the CAD building drawings; c, performing building component recognition, visibility analysis and three-dimensional positioning on each layer of plane drawing of the CAD building drawing; d, carrying out bounding box construction on the elevation drawing paper in each direction ofthe CAD building drawing paper, and carrying out search and size measurement on the elevation drawing component; according to the method, when the CAD building drawing is converted into the three-dimensional BIM model, the components of the elevation map of the CAD building drawing are recognized, the size numerical value of the components is obtained, and the CAD building drawing recognition andthree-dimensional BIM model reconstruction efficiency is improved.