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P-TDR is a new time-domain reflectometry based on the phase detection principle. It measures the travel time of testing signal by detecting phase difference of the incident and reflected waves, and thereby calculates the soil moisture content. The PTDR measurement accuracy of soil moisture content reaches the level of the traditional TDR. But if it is used to measure soil conductivity (σ) by detecting the testing signal reflectivity (ρ), verification is necessary. The measurement method of soil conductivity and the principle of P-TDR were introduced firstly. Then an experiment was arranged. The testing signal reflectivity of P-TDR was measured in 8 sandy loam soil samples, which had different salt contents under five levels of soil moisture content (θ). The relationship between ρ and σ was modeled respectively by using linear and quadratic polynomial model, and the quadratic polynomial was chose for PTDR electrical conductivity measurement model, whose determination coefficient was above 0.812. The experiment results also showed that soil moisture content had greater influence on the electrical conductivity measurement. After the analysis of the relationship between soil moisture and the quadratic polynomial coefficients, the predictive model of soil electrical conductivity, which is the function of ρ and θ, was established. The experiments of in-situ measurements are needed to research the influence of factors such as soil texture on the P-TDR soil conductivity measurement. 