Abstract: Aiming at the problems of the difficulty in ensuring the accuracy of the thickness of the spacecraft's thin-walled cabin and the low processing efficiency, the on-machine measurement and compensation method of the wall thickness of the thin-walled parts are studied based on the ultrasonic touch probe. First, the ultrasonic touch probe is used to measure the thickness of the thin-walled parts and the external profile, and the external profile deviation and thickness deviation are compensated at the same time. The compensation value calculation and optimization method is designed to calculate the corresponding lightening groove compensation value. Then, develop the post-processing of NX programming software, the compensation value is automatically compensated to the NC machining program,realize the on-machine measurement and compensation processing of the wall thickness of the thin-walled parts automatically, and improve the processing efficiency and quality stability.