The electroreduction of carbon dioxide (CO<sub>2</sub> ) has been emerging as a high- potential approach for CO<sub>2</sub> utilization using renewables. When copper (Cu) based catalysts are used, this platform can produce multi-carbon (C<sub>2+</sub> ) fuels and chemicals with almost net-zero emission, contributing to the closure of the anthropogenic carbon cycle. Nonetheless, the rational design and development of Cu-based catalysts are critical toward the realization of highly selective and efficient CO<sub>2</sub> electroreduction. In this review, first the latest advances in Cu-catalyzed CO<sub>2</sub> electroreduction in the product selectivity and electrocatalytic activity are briefly summarized. Then, recent theoretical and mechanistic studies of CO<sub>2</sub> electroreduction on Cu-based catalysts are investigated, which serve as programs to design catalysts. Strategies for devising Cu catalysts that aim at promoting different key elementary steps for hydrocarbon and C<sub>2+</sub> oxygenates production are further summarized. Moreover, challenges in understanding the mechanism, operando investigation of Cu catalysts and reactions, and systems' influences are also presented. Finally, the future prospects of CO<sub>2</sub> electroreduction are discussed.