Non-contact on-machine measurement method for rotary body part

The invention provides a non-contact on-machine measurement method for a rotary body part. The non-contact on-machine measurement method comprises the following steps: adjusting the axis of a spectrum confocal measuring head to be approximately parallel to the Z axis of a machine tool; measuring a first deviation value of the axis of the spectral confocal measuring head and the Z axis in the Y-axis direction, measuring a second deviation value of the axis of the spectral confocal measuring head and the Z axis in the X-axis direction, and adjusting the first deviation value and the second deviation value to be smaller than a preset value; adjusting a light spot of the spectrum confocal measuring head to enable the light spot to be located at the central position of the measuring surface; the spectrum confocal measuring head is driven to move in the Y-axis direction, the spectrum confocal measuring head is stopped at the position with the minimum distance or the maximum distance away from the measuring face, an