Abstract: The paper introduces a new way to measure the stretch sensitivity of piezoelectric ceramic.We use the helium-neon gas laser＇s analysis apparatus to measure the voltage increment of corresponding sequence＇s two adjacent interference lines and calculate the elongation.This process can be used to measure expediently and accurately the sensitivity of piezoelectric ceramics convenient.

Key words: spherical confocal scanning interferometer, piezoelectric ceramic（PZT）, dilation