Abstract: The procedure of cadmium ion transport through unsaturated soils can be described by the convection-diffusion equation,coupled with non-equilibrium sorption effect.The undetermined model parameters in the dimensionless governing equation include the longitudinal dispersivity,the sorption distribution coefficient,the precipitating rate,the dissolving rate and the maximum precipitation.This paper aims at inversing parameter values of the parameter mentioned above for cadmium ion transport in 8 Portugal soils samples and.Belgium soils sample under different experimental conditions.Experimental results of 15 groups are obtained in virtue of the laboratory soil column tests for 9 soils samples mentioned above by using self-designed experimental apparatus under different experimental condition.The gradient regularization method is adopted as the inversion method.Based on the experimental results (BTCs),the corresponding model parameters for each experiment are identified by the numerical inversion.The validity and reliability of the gradient regularization method is verified by the numerical simulated experimental results.The computational results confirm the veracity of results presented in this paper.