Method for measuring outer circumference and maximum and minimum diameters of cylindrical workpiece

The invention relates to a method for measuring the outer circumference and maximum and minimum diameters of a cylindrical workpiece. The method comprises the following steps of: measuring device preparation; and data measuring and recording. According to the measuring device preparation step, a laser displacement sensor is adopted; and the laser displacement sensor rotates around a to-be-measuredcylindrical workpiece or the to-be-measured cylindrical workpiece rotates around the center axis of the to-be-measured cylindrical workpiece and the laser displacement sensor is stationary. Accordingto the data measuring and recording step, M measuring points are selected from the to-be-measured cylindrical workpiece; measurement is initiated; with every four points taken as a group, the measurement data of every four points are fitted into a circle according to a certain rule; the sum of the arc lengths of two diagonal short arcs is calculated, so that the diameter and arc length of the four-point group is obtained;