The invention discloses a measuring method, apparatus and system of a standard enlarged drawing. The measuring method includes: converting a to-be-measured standard enlarged drawing to a corresponding three-dimensional model graph according to an entity model requirement thereof; extracting first coordinate values corresponding to a plurality of theoretical metering points of the to-be-measured standard enlarged drawing, and storing the first coordinate values in a first file; importing the three-dimensional model graph to the measuring system, and establishing a measuring coordinate system in the measuring system according to the center line of the to-be-measured standard enlarged drawing; importing the first file to the measuring system, and measuring second coordinate values corresponding to the plurality of theoretical metering points in the measuring system; and determining whether the linear profile corresponding to the to-be-measured standard enlarged drawing is in accordance with a theoretical linear profile requirement according to a characteristic combination formed by the second coordinate values. According to the measuring method, global fitting can be realized, whether the linear profile is in accordance with the theoretical requirement is determined according to the characteristic combination formed by the second coordinate values, and the calibration of the linear profile is more accurate.