为了提高光学折射法海水盐度检测精度，综合分析现有检测方法，认为其海水盐度检测精度低的主要原因是其检测光路为平行平板模型。由此，提出了棱镜模型多次折射法检测方案。利用棱镜模型而不是平行平板模型，提高了光线的偏折角；通过设置多个棱镜模块，进一步扩大偏折角，从而大大提高系统的分辨力。设计了光路并进行仿真分析，研制了样机并进行了海上实验。结果表明，盐度检测的分辨力达0.0012‰，重复性不大于±0.016‰。由海上与ALEC温盐传感器比测实验表明，与ALEC传感器一致性好，稳定性好，比测误差在±0.1‰以内。

A seawater salinity measurement system based on prism model multi-refraction is presented in order to improve the salinity measurement precision using optics refraction. The beam angle of refraction is expanded by using prism model other than parallel model, and is enlarged by setting multiple-prism-units further. So the measurement precision is improved greatly. The measurement system is developed after design and simulation. After laboratory experiments and sea experiments with ALEC sensor, it is indicated that the developed system is effective with a measurement resolution of 0.0012‰, repeatability error less than ±0.016‰, and measurement error less than ±0.1‰ compared with ALEC sensor.