Abstract: Brachytherapy can kill cancer cells more effectively and make the normal tissues around the tumor free or less irradiated. It has become an effective means for the treatment of malignant tumors. ¹⁰³Pd has a half-life of 16.96 days and a significant advantage in the field of brachytherapy due to its unique decay properties. In order to achieve the large-scale production of ¹⁰³Pd, the preparation process based on Cyclone-30(C30) cyclotron was studied. The rhodium metal was electroplated on the copper target base by pulse electroplating method. The rhodium-plated target was transferred to C30 solid target station for irradiation with beam energy of 16-18 MeV, and the beam current was 200 μA. In order to obtain Curie-level ¹⁰³Pd, the beam integral should be more than 10000 μA•h. After irradiation, the target was transferred to the separation and purification hot cell, the rhodium plating was separated from the target base first, then was ground into powder, and dissolved by high temperature melting of potassium bisulfate. The rhodium was converted into soluble rhodium sulfate, and the ¹⁰³Pd nuclide was separated and purified by AG1-X8 resin. The impurities of Rh, Fe, Cu and Zn were rinsed with 6 mol/L hydrochloric acid and 0.03 mol/L hydrochloric acid, respectively. At last, ¹⁰³Pd was desorbed with a mixed solution of ammonium chloride-ammonia mixed solution(volume ratio 1∶1). The radioactive activity, radionuclide purity and specific activity of ¹⁰³Pd were measured respectively. The preparation of sealed seed core was studied by using the prepared ¹⁰³Pd feed solution. The results show that the rhodium plating layer is smooth and dense, and firmly bonded with the copper plate, the rhodium layers mass thickness is greater than 150 mg/cm². The production capacity of ¹⁰³Pd is greater than 37 GBq, the radionuclide purity is greater than 99.9%, and the specific activity is greater than 875 GBq/mg, and activity concentrations greater than 6.2 GBq/mL. The preparation field of ¹⁰³Pd brachytherapy sources is more than 90%, it can meet the requirements. The ¹⁰³Pd preparation process is stable, and the quality is controllable. The large-scale production capacity has been reached, and it provides a stable source for the research of ¹⁰³Pd brachytherapy sources.