Batch experiments were performed to study the dependence of Th(IV) absorption by insoluble humic acid (IHA) on IHA dosage, reaction time, pH、initial concentration and temperature etc. Absorption kinetics, Isotherms and thermodynamics were investigated. Absorption mechanics were also analysed with the help of Scanning Electron Microscope (SEM) and Fourier Transform Infra-Red Spectroscopy (FTIR). The experimental results of the maximum removal rate can be made to increase by 78.6% at an initial concentration of 50 mg/L，the pH value of 3.50 and in an adsorbent dose of 1. 00 g/L at 30.0 ?C till the equilibrium state is expected to arrive in approximately 6.00 hours. thermodynamic analysis suggests this reaction is endothermic and satisfies Freundlich Isotherms according to >0.900 correlation coefficient R2. Absorption kinetics agrees with pseudo-second-order kinetic plot, with R2=0.995. After carboxyl and phenolic hydroxyl reacted with Th(IV), IHA had a modified surface. From above, Th(IV) absorption by IHA can be considered as surface complex.