Line width measuring method and line width measuring machine

The embodiment of the invention discloses a line width measuring method and a line width measuring machine. The method comprises the steps of enabling a camera shooting assembly to collect a visual field image of a measured product; intercepting a visual field image to obtain a first measurement image of the measured product; performing alignment according to the deviation of a marker in the firstmeasurement image, and intercepting a second measurement image; calculating an image deviation according to the second measurement image and a preset image; intercepting a third measurement image according to the image deviation; wherein the third measurement image comprises a measurement part of the measured product; the line width of the measuring part is measured and calculated according to the image of the measuring part. According to the embodiment of the invention, the problem that the line width measurement of the measured product fails in the automatic measurement process of the linewidth measurement machine