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In order to solve the problem of inaccurate measurement of soil electrical conductivity sensor, a nonlinear coupling calibration model without considering water content θ within considering θ was proposed, and the calibration and verification tests of soil electrical conductivity sensor were carried out. The calibration test was conducted by using the sandy soil of the apple orchard in the 10th Regiment, Xinjiang Alar, China. With deionized water and NaCl, totally nine group of moisture content gradients and six groups of salinity gradients, 54 soil samples were designed. The electrical conductivity of soil samples was measured by soil electrical conductivity sensor and high precision conductivity meter respectively. According to the coupling model, the three treatments without θ, with θ and with θ subdivision were fitted respectively. Finally, a field verification test was designed for the same apple orchard. The results showed that the conductivity EC0 measured by soil electrical conductivity sensor and conductivity EC1 measured by conductivity meter were positively correlated with the soil salt content. However, EC0 was increased with the increase of θ, while EC1 was decreased with the increase of θ. The results of cubic fitting showed that θ had a significant effect on the measurement of electrical conductivity, and the residual of the cubic fitting was decreased gradually with θ subdivision. The fitting determination coefficients R2 were not less than 0.839, which were gradually increased, and the fitting accuracy was increased. The verification test results showed that the proposed coupling model could effectively improve the measurement accuracy of soil electrical conductivity. The calibration method can provide a basis for the accurate measurement of soil conductivity and the calibration of soil conductivity sensors.