The use of soil dielectric properties as an indirect measurement of volumetric moisture content is accepted in a wide range of disciplines. Empirical relationship was studied between soil dielectric constant and volumetric water content in eight soils of four types, i.e.. fluvo-aquci soil, aeolian sandy soil, red soil, and paddy soil. Based on soil column experiments, the Topp’s equation (1980) was amended, and correction factors a and b of the Herkelrath (1991) equation were verified. Results show that the prediction of soil volumetric moisture content using the Topp’s equation was relatively big in error for sandy loam fluvo-aquci soil, silty clay fluvo-aquci soil, aeolian sandy soil, and clay red soil. Compared with thr Topp’s equation (1980), the Topp fitting equation was optimized, but its effect was not satisfactory with errors being still quite big in predicting volumetric moisture contents various in range, especially for clay red soil. The Herkelrath fitting equation was relatively better for all the four types of soils, and could be cited as the first priority choice for application. All the three relationship equations were quite good in predicting volumetric moisture content in the two paddy soils different in texture, with the mean absolute error being less than 0.03 cm³ cm^-3.