Abstract: In order to study the migration and distribution characteristics of contaminated cadmium Cd in typical paddy soil in Chengdu Plain during irrigation,the applicability of VG-TSM （two-point adsorption） model is verified.Based on the dynamic soil column test,three irriga-tion modes of exogenous Cd solution water injection+clear water leaching quota are designed to simulate the Cd migration characteristics un-der different pollution scenarios,and the VG-TSM model in Hydrus-1D software is used for fitting verification,prediction analysis and sen-sitivity analysis of soil column test results.The results show that the penetration ability of Cd in soil is affected by irrigation mode.The greater the water injection amount of Cd,the weaker the adsorption buffer effect of soil,and the higher the peak concentration.Through the fitting analysis of root mean square error RMSE,correlation coefficient R~2 and average absolute error MAE,it is found that the simulated value is in good agreement with the measured value,which proves the rationality of the spatio-temporal migration model of Hydrus-1D-Cd solution.Ex-tending the simulation time,it is found that the further analytical release characteristics of Cd in soil are consistent with the TSM model of chemical non-equilibrium solutes.Through parameter sensitivity analysis,the hydraulic characteristic parameters θ_S and K_S under the con-trol of VG model,and the solute transport parametersρ，K_d and f under the control of TSM model have a profound influence on the simulation output results.In addition,soil texture,soil column test scale,irrigation mode and other factors may also affect parameter sensitivity and cause irrational fluctuation of simulation results.