Electrochemical CO2 reduction reaction (CO2RR) has been widely studied as a solution for environmental and energy issues. Electrolyte, as an essential component in all kinds of cells, plays a key role in the stability and activity of electrolysis systems. Up to now, alkaline, neutral, and recently emerging acidic solutions are used in most state-of-the-art electrolyzers. However, these electrolytes will cause a stability decay of both electrocatalysts and electrolyzers and an increase in total expense. Oppositely, pure water-fed electrolyzers enable a stable and low-cost electrolysis process, although some challenges remain. This review focuses on the electrolytes in different electrolyzer configurations and covers the efforts on the design strategies to drive CO2RR in pure water. We also propose the potentials and challenges for realizing CO2RR in pure water, which will be helpful on the technological innovations of manufacturing electrodes, designing cells, and characterizing methods for deeper understanding in pure water-fed CO2RR.