The invention discloses a method and a device for measuring thickness of a
numerical control machining workpiece and is suitable for online thickness measurement in the
numerical control machining process. The measuring method comprises the following steps of: manufacturing a circular groove for storing a
coupling agent on a blank, setting detection points, extracting coordinates of the detection points, planning a detection path, and generating a
numerical control program; transmitting the numerical control program to a numerically-controlled
machine tool, controlling the
machine tool to move, and automatically triggering an ultrasonic probe to measure through a terminal processor once the
machine tool moves to a point; and finally, transmitting the measuring data to the terminal processor. The thickness measuring device consists of a knife
handle connecting device, an ultrasonic probe, a
data transmission line and a terminal processor, wherein one end of the knife
handle connecting device is connected with the ultrasonic probe; the other end of the knife
handle connecting device is connected with the knife handle of a
machine tool spindle, so that numerical control motion of the probe is realized; and the terminal processor can be a
personal computer (PC) of a
numerical control system and can be connected with the PC of the
numerical control system. By the method and the device, the thickness of the numerical control
machining workpiece is automatically measured on line, and the thickness measuring efficiency is greatly improved.