The semi-theoretical and empirical calibration curve,θ_v=(T/T_a-T_s/T_a)/(K_w^0.5-1),soil water content(θ_v) versus propagation time(T)of electromagnetic wave along TDR probe inserted in soil,is used to calculate soil water content.In this experiment TDR is used to measure T_s/T_a value of oven-dried soils with different texture and bulk density.The result showed that T_s/T_a value from 1.61 to 1.80 for four soils,and the larger bulk density,the larger T_s/T_a value.For three agricultural soils the average T_s/T_a can be used as 1.68.The column experiments on sandy loam and loam showed(water content from oven-dry to saturation) that different T_s/T_a values lead to water content deviation 0.001~-0.005 cm³ /cm³ and 0.007~-0.006cm³/cm³ respectively.For sandy loam with varied soil temperature,water content measured by TDR deviated from real values when it is higher than 0.30 cm³/cm³.The higher temperature,the lower water content measured.This paper also indicates the deviation range of measured water content with temperature increasing(or decreasing) 1℃ and its modification method.