Abstract: Expansion quantity at high temperature is transferred to room temperature by quartz staff,and additive effect deriving from transformation is eliminated by confirming standard.A self-restraint apparatus is made to measure the thermal expansion coefficient,and measuring principle is based on the measuring the micro-displacement by Michelson interferometer;the relative error only is 1.0%,moreover,the measuring process is simple.

Key words: thermal expansion coefficient, interferometer, measurement