In order to measure materials of 3-D hermal expansion coefficient under the condition of the bad environment,a novel method was proposed in this paper.The thermal expansion coefficience of the new material was measured by using a Fiber Bragg Grating sensor.The results of experiment indicate that this method could be full of credibility in examining the thermal expansion coefficient under the condition of the bad environment,at of the large-scale temperature of bellowing to negative 50℃ and highing to 150℃ the FBG could also be in a good working condition.The text gave the theory correspondence and the results of experiment.