The leaching and adsorption of gold in thiosulphate resin-solution (TRS) system requires reliable reaction mechanism and model to solve all the species in the TRS system in order to maximize gold thiosulphate complexes being adsorben on resins. This work proposed the development of simultaneous leaching and adsorption model for gold thiosulphate complexes in the TRS system. The model was solved using the multi-dimensional Newton-Raphson and Levenberg-Marquardt methods. It was validated against experimental data, and the result showed that the model-based result was in a very good agreement with the experiment data with correlation coefficient, R2 being 0.987. The results also clarified the effect of initial concentration of thiosulphate, sulphite and trithionate on the adsorption of gold thiosulphate complexes. The isotherm adsorption of gold thiosulphate complexes exponentially increased over time. The gold thiosulphate species on resin, R3Au(S2O3)2 increased with the increase in the initial thiosulphate concentration, but R3Au(S2O3)(SO3) and R5Au(S2O3)(SO3)2 had contradictory trends. Overall, minimizing trithionate on resin by limiting the initial suphite concentration in the TRS system, and controlling the initial thiosulphate concentration in the constraint can play important role to maximize the amount of desired species, R3Au(S2O3)2, R3Au(S2O3)(SO3) or R5Au(S2O3)(SO3)2.