Chord line-based measurement method for blade processing distortion error

The invention discloses a chord line-based measurement method for a blade processing distortion error. The method comprises four stages of three-dimensional solid construction, solid data measurement,data analyzing and processing and error analysis, wherein the three-dimensional solid construction is to describe a blade surface through a free surface in a design software CAD/CAM to provide a design model for error analysis; in the solid data measurement process, measurement is carried out by adopting a contact-type three-coordinate measurement method, so that the measurement accuracy is higher than non-contact measurement accuracy, furthermore, millions of data points can be obtained through one detection by adopting a scanning mode and the measurement accuracy can reach 0.01mm; and in the data analyzing and processing process, noise removal, data merging and region partitioning are carried out. According to the method disclosed by the invention, the detection result of the blade processing distortion error i