Carbon dioxide, as a greenhouse gas, is expected to be converted into other useful substances by the electrocatalytic CO₂ reduction reaction (CO₂RR) technology. The electrocatalytic cell, or electrochemical cell, used to provide the experimental environment for CO₂RR plays an irreplaceable role in the study of this process and determines the success or failure of the measurements. In recent years, electrolytic cells that can be applied to in-situ/operational synchrotron radiation (SR) characterization techniques have gradually gained widespread attention. However, the design and understanding of electrolyte systems that can be applied to in-situ/operational SR technologies are still not sufficiently advanced. In this paper, the electrocatalytic cells used to study the CO₂RR processes with in-situ/operando SR techniques are briefly introduced, and the types and characteristics of the electrolytic cells are analyzed. The recent advancements of in situ/operando electrolytic cells are discussed using X-ray scattering, X-ray absorption spectroscopy (XAS), light vibration spectroscopy, and X-ray combined techniques. An outlook is provided on the future prospects of this research field. This review facilitates the understanding of the reduction process and electrocatalytic mechanism of CO₂RR at the atomic and molecular scales, providing insights for the design of electrolysis cells applicable to SR technologies and accelerating the development of more efficient and sustainable carbon negative technologies.