Abstract: A novel method was developed to automatically measure the delicate high-frequency components of Ku-band space traveling wave tube(TWT),the irregularly shaped thin-wall tube with a large aspect-ratio in particular,with a lab-modified conventional image-measurement instrument,operating in probe & video mode.The original work included:a self-developed sample-holding mold,a new algorithm for horizontal sample positioning and alignment based on Y-coordinate of the feature point,and self-developed software.Besides,the sources of measurement errors were found out and effectively reduced.The non-destructive,high precision measurements were realized.The test results show that the newly-developed measurement technique does a good job.However,when it comes to measurement of the irregularly-shaped thin-wall tube,many times longer than 4 mm(upper depth-limit) and in a diameter of 2.45 mm for Ka-band and 1.6 mm for V-band,much research work remained to be done.