Abstract: Gallium ⁶⁸Ga is an important positron-emitting radionuclide in PET imaging radiopharmaceuticals. In order to ensure that the quality of gallium ⁶⁸Ga solution, a key raw material of gallium ⁶⁸Ga radiopharmaceuticals, meets the requirements of high labeling efficiency and safety, a detailed study on impurities in gallium ⁶⁸Ga solution from the generator was carried out, analytical method for impurity detection was developed and the validation of the methodology was completed. To control radiochemical impurities, radioactive thin-layer chromatography (Radio-TLC) method was used. The effects of key variables such as mobile phase, pH of the mobile phase, and system suitability solution on the test results were studied. After method optimization, iTLC-SG was determined to be the stationary phase, methanol-1 mol/L ammonium acetate (1∶1, V/V, ammonium acetate pH=2.8±0.2) as the mobile phase. In order to control elemental impurities, twelve elements including Fe, Ni, Zn, Sb, Pb, Li, V, Co, Cu, As, Cd, and Hg were determined by inductively coupled plasma mass spectrometry (ICP-MS) method. The radionuclide purity was determined by high-purity germanium (HPGe) γ spectroscopy, and the γ nuclide impurities such as ⁶⁸Ge were controlled. Combined with the properties of the samples and the characteristics of each analytical method, the established analytical methods were validated. The validation included system suitability and resolution, linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, precision, durability, etc. These validated methods were used to determine impurities in gallium-⁶⁸Ga chloride solutions. The impurity test results of gallium-⁶⁸Ga chloride solution show that the Rf of ⁶⁸Ga³⁺ is ≤0.2, and its radiochemical purity is 99.04%±0.35% (n=3). Its iron content is ≤0.5 μg/GBq, zinc content is ≤0.1 μg/GBq, and other elements do not exceed 30% of the PDE limits. Gallium ⁶⁸Ga radionuclide purity is more than 99.9%, other γ nuclide impurities are not detected at the first detection. 24 hours later, germanium ⁶⁸Ge breakthrough and other γ nuclide impurity content is 0.000 19%±0.000 05% (n=3). The results show that the established analytical methods can accurately determine the impurity of gallium-⁶⁸Ga chloride solution and effectively control its quality. The impurity content is lower than the limit required by European Pharmacopoeia (EP10.0). The successfully established detection method for impurities of gallium-⁶⁸Ga chloride solution provides a reference for the impurity control of medical radionuclides and the establishment of quality standards.