为了精确得到三元结构的λ／4消色差复合波片的消色差范围，采用数学解析的方法进行了理论分析，并在中心波长600nm处进行实验，得到偏差在2%以内的光谱范围大约为540nm～680nm。结果表明，其消色差范围只在中心波长的附近，这一结果对实验中棱镜的选用是有帮助的。

In order to find the achromatic scope of three-element compound λ/4 wave-plate,mathematical analysis was performanced and experiments at the center wavelength of 600nm was executed. In the experiment the spectrum range was between 540nm～680nm when the deviation is less than 2%. It is concluded that the achromatic scope is only near the center wavelength,which is very important for practiceal prism selection.