The polluted sandy soils by rapeseed oil and motor oil were prepared artificially and then the correlation of the contents of the non-aqueous phase liquids (NAPLs) with soil dielectric properties and electrical conductivity was investigated with time domain reflectometry (TDR). The dielectric mixing model was used to predict NAPLs content and then calibrated by fitting a parameter of α. The results showed that soil dielectric constant did not change with oil content (v/v) below 0.05 cm³/cm³ in the saturated sandy soil. However, soil dielectric constant decreased with the increasing NAPLs content linearly above the oil content of 0.05 cm³/cm³. Soil bulk density and the types of NAPLs did not affect soil dielectric constant for the same saturation of the soil. There was a linear negative correlation between the NAPLs content and soil electrical conductivity with R²=0.96. Soil bulk density did not affect electrical conductivity for the same saturation of the soil. The dielectric mixed model with α=0.5 overestimated the NAPLs content in the saturated sandy soil, with the average root mean square error of 0.038 cm³/cm³. After adjusting the parameter? α ?to 0.52, the predicting accuracy of the dielectric mixed model was increased by 23.2%. Therefore, TDR can be applied to determine the contents of NAPLs in contaminated soils.