为了实现低温真空环境下红外材料热膨胀系数的高精度测量，提出了一种固体材料低温热膨胀系数的测量方案。本方案基于自准直原理，设计了一种测微结构，建立起了结构变形与角度的关系，并推导出热膨胀系数测量公式。利用测量公式，从理论上分析了该方案的测量误差传递函数关系，并利用误差灵敏度函数对红外材料低温热膨胀系数测量装置的设计精度进行了分析，最后通过计算得到了该方案的测量相对误差。结果表明，测量的热膨胀系数相对误差仅为0.76%，满足纳米级测量要求。

In order to realize the high-precision measurement of the thermal expansion coefficient of the infrared material under the cryogenic vacuum environment, a measurement scheme of solid material is proposed. Based on the self-collimation principle, this scheme designs a microstructure, establishes the relationship between structural deformation and angle, and deduces the formula of thermal expansion coefficient measurement. Us-ing the measurement formula, this article analyzes the relationship between the measurement error transfer function of the scheme, and also uses the error sensitivity function to analyze the design accuracy of cryogenic thermal expansion coefficient measuring device for infrared materials, and finally the relative error of the scheme is calculated. The thermal expansion coefficient of the scheme is measured to be only 0.76%, which satisfies the nanometer measurement requirement.