准确的测量薄膜的厚度和光学常数，在薄膜的制备、研究和应用中都是十分重要的。借助Cauchy色散模型，通过薄膜透过率测量曲线，用改进的自适应模拟退火遗传算法对透过率曲线进行全光谱拟合，从而反演得到薄膜的厚度和光学常数。对由电子束蒸发制备的TiO2单层膜和SiO2/TiO2双层膜的厚度和光学常数进行了测量计算。实验结果表明，计算得到的光学参数与实测结果相一致，厚度误差小于2nm，在560nm波长处折射率误差小于0.03。

It is very important to measure thickness and optical constants accurately for film fabrication，research and applicatiom. With Cauchy dispersion model, the optical constants and thickness of thin film are inversed by fitting the curve of transmission spectrum using whole optical spectrum fitting based on adaptive simulated annealing genetic algorithm. The results of TiO2 and SiO2/TiO2 thin films deposited by electron beam evaporation respectively are in good agreement with the measuring. The experimental result shows that the calculated transmittance of the film is consistent with the measured value. The thickness error is less than 2nm, and the refractive index error at 560nm is less than 0.03.