Driven by the dual impetus of ever-increasing global energy demand and advancement of the “carbon neutrality” strategic goal， the electrocatalytic CO₂ reduction reaction has emerged as a critical technology for achieving the cyclic utilization of carbon resources. Consequently， there is an extremely urgent need for advancements towards higher efficiency and lower cost. Copper-based catalysts have distinguished themselves as the leading candidates among numerous catalysts due to the abundant natural reserves， low cost， and unique d-orbital electronic structure. As such， they have become a central research focus and a frontier direction in the field of electrocatalytic CO₂ reduction. In recent years， a series of significant breakthroughs have been made in the structural design and performance modulation of copper-based catalysts. These substantially contributed greatly to the synergistic optimization of catalytic activity， long-term operational stability， and product selectivity. Herein， this review systematically summarizes the fundamental reaction mechanisms responsible for the electrocatalytic CO₂ reduction to various target products over copper-based catalysts. Furthermore， it demonstrates the employment of critical reaction parameters， theoretical calculation methods， and advanced characterization techniques in deducing and verifying the proposed reaction mechanisms. Also， the core pathways for constructing high-performance copper-based catalysts are discussed and the emphasis is placed on deliberate strategies such as composition regulation， structural optimization， morphology modification and so on. In view of providing valuable insights for the rational design of highly efficient and durable copper-based catalytic systems， this paper strives to outline the precise design principles of copper-based catalysts and establish a comprehensive correlation framework that connects specific modulation strategies with the resulting catalytic performance.