Abstract: Soluble salt ion in the soil is one of the factors restricting the crop growth.The soil complex dielectric constant is an important indicator for determining the soluble salts in the soil.In this paper,we measured the dielectric constants of 4 electrolyte aqueous solutions by the resonant cavity technique,and obtained complex influence factors with 5 ions including Na⁺,CI^-,SO₄^2-,CO₃^2- and HCO₃^- at 25℃.By using the complex influence factor of each ion,we directly applied the Collie dielectric model to calculate the real part of the dielectric constant of the electrolyte aqueous solution.In order to test the accuracy of the model,we simulated 41 soil solutions of chloride type,sulfate type and soda type; substituted the influence factors of single electrolyte NaCl,Na₂SO₄ and NaHCO₃ aqueous solutions for the complex influence factors of chloride type,sulfate type and soda type saline soil solutions,respectively.We used correlation analysis t test to calculate the dielectric constant value of the improved Collie dielectric model and simulated the measurement results from the above 41 soil solutions.The results showed all the P values were above 0.85 with no significant differences (P>0.05).The data of the two groups showed a good consistency.Therefore,the results would lay a solid foundation to establish a microwave remote sensing dielectric model for monitoring salinity of saline soil and salt lake water.