Abstract: ⁹⁹Tc^m (T_1/2=6.01 h) is the decay daughter of ⁹⁹Mo, which is one of the most widely used radionuclides in clinical diagnosis of nuclear medicine. However, ⁹⁹Tc^m obtained by the existing production methods requires chemical purification and separation steps, and the operation is complicated. Therefore, it is of great practical significance to study the separation behavior of Mo(Ⅵ)/Tc(Ⅶ). TK202 resin was developed by Triskem company for the efficient separation of Mo(Ⅵ)/Tc(Ⅶ). The skeleton of TK202 resin is polystyrene, and the extraction functional group is polyethylene glycol, which shows excellent separation effect on Mo(Ⅵ)/Tc(Ⅶ), but there is no relevant report to systematically investigate the separation behavior of Mo(Ⅵ)/Tc(Ⅶ) onto TK202 resin. In this work, the separation of Mo(Ⅵ)/Tc(Ⅶ) by TK202 resin was overall studied by batch experiments, the effects of different factors, including alkali concentration, equilibrium time, interfering ions and high-temperature roasting, on the adsorption of Tc(Ⅶ) (Re(Ⅶ) as an analog) by TK202 resin were investigated. The working capacity of Re(Ⅶ) onto TK202 resin and the dynamic separation of Mo(Ⅵ) and Re(Ⅶ) were explored by column experiments, and the adsorption mechanism was explored and analyzed through different characterization techniques. The results show that the adsorption effect of TK202 resin on Re(Ⅶ) is the best, and the K_d is 118 mL/g when the concentration of NaOH is 7 mol/L. The adsorption kinetics conform to the pseudo-second-order kinetic model, and the adsorption isotherm conform to the Freundlich model. In 7 mol/L NaOH solution, MoO₄^2- is not captured by TK202 resin, and its presence can promote the adsorption of Re(Ⅶ) on the resin. After calcination at high temperature, the adsorption ratio of Re (Ⅶ) on TK202 resin gradually decreases. When the calcination temperature exceeds 200 °C, the structure of the resin is decomposed, and its adsorption capacity for Re(Ⅶ) is further reduced. In addition, the results of reuse performance show that the adsorption ratio of Re(Ⅶ) on TK202 resin decreases significantly after 5 adsorption-desorption cycles, which may be due to the destruction of resin structure during desorption process. Dynamic column experiments show that the adsorption capacity of TK202 resin for Re(Ⅶ) is 7.89 mg/g, and the separation efficiency of Mo(Ⅵ)/Tc(Ⅶ) and the recovery of Re(Ⅶ) are near to 100%. According to the experimental and characterization results, the adsorption mechanism of Re(Ⅶ) by TK202 resin is that the salt solution and polyethylene glycol (PEG) form a dual aqueous phase system, which is related to the hydrated Gibbs free energy of the anion in the salt solution, and the hydrated Gibbs free energy moves to the salt-rich phase and the small one moves to the PEG phase. In summary, this work explores the Mo(Ⅵ)/Tc(Ⅶ) separation behavior in detail, which provides a certain experimental basis for the practical application of TK202 resin in Mo(Ⅵ)/Tc(Ⅶ) separation.