在分析常用快速测定方法基础上从低成本快速测试的目标出发提出了实现土样含水量速测用电容传感器结构和原理,对电容传感器研制中存在的问题提出了解决办法. 从使用电容传感器测试土样水分结果与常规烘干称重法对比来看,其精度达到土样含水量测定的要求. 关键词:电容传感器; 土样; 介电常数; 数学模型 Abstract : The problems of traditional testing methods are analyzed , and the capacitance sensor technique is presented for fast and cheap testing of water content in soil . The sensor designing principle and construction are also discussed. The problems have been solved in developing the capacitance sensor. The testing precision of the instrument based on this technique is equivalent with that by the traditional drying and weighing method. The precision can meet the testing requirement of water content in a soil sample. Key words : capacitance sensor ; soil sample ; dielectric constant ; mathematical model