Abstract: ¹³¹Cs is an important radioactive medical nuclide with significant applications in nuclear medicine field, such as myocardial imaging, thyroid nodule detection and scanning, and interstitial brachytherapy for malignant tumors including prostate cancer, breast cancer, head and neck cancer, lung cancer, brain metastases, etc. The nuclide ¹³¹Cs can be produced through the acceleration of charged particles, such as protons (p) or alpha particles (α), in an accelerator to bombard appropriate targets. Additionally, it can be produced by using thermal neutrons in a reactor to irradiate corresponding targets. However, the yield of ¹³¹Cs produced by accelerators is relatively low, making it impossible to achieve large-scale preparation of ¹³¹Cs. Therefore, ¹³¹Cs is typically obtained indirectly by bombarding a Ba target (natural Ba or enriched ¹³⁰Ba) with thermal neutrons in a reactor, resulting in the formation of ¹³¹Ba (T_1/2=11.5 d), which subsequently decays via electron capture to form ¹³¹Cs (T_1/2=9.7 d). The nuclear reaction is ¹³⁰Ba(n, γ)¹³¹Ba → ¹³¹Cs. Subsequently, the separation of Ba/¹³¹Cs and purification of ¹³¹Cs are achieved through a combination of precipitation and column chromatography methods. However, the existing Ba/¹³¹Cs separation processes face issues such as complex separation procedures, large volumes of liquid waste production, and time-consuming for separation. Therefore, improving the Ba/¹³¹Cs separation and purification process to address the current limitations is of significant scientific value, especially given that large-scale preparation of ¹³¹Cs and ¹³¹Cs seeds is not yet realized in China. In light of this, this study briefly summarizes the separation status of Ba/¹³¹Cs and the application status of ¹³¹Cs, providing a reference for the preparation and application of ¹³¹Cs nuclide in China.