在中医理论里，舌体的水份含量是舌诊的重要参考依据。现有的测量方法在可重复性和测量精度上 都不够理想。为此，提出了一种基于质传递速率方法的新型舌体水份含量测量仪，采用数字式温湿度传感器， 详细阐明了检测原理、软硬件设计与实现方法。该测量仪有小型便携、操作简便、低功耗等优点，并通过实验 证明比现有测量方法具有更好的性能，测量值标准偏差为2.9％，能快速准确地反映舌体干湿润燥程度。

In traditional Chinese medicine, tongue moisture plays an important role in tongue diagnosis.  However, there are still some problems in conventional measurement. Therefore, a hygroscope, which uses digital humidity and temperature sensor, was developed to test tongue moisture based on mass transfer means.  This paper presents its testing principle and the design method of its hardware and software. This hygroscope finds itself with some attractive features, such as portability, handy operation, low power consumption, etc. It has been proved that the standard deviation of this tester, only 2.9%, is better than that of other conventional instruments, and the tongue moisture could be measured rapidly and accurately.