The explosion in demand for lithium resources has made the extraction of lithium from lithium-rich brines in salt lakes a current research hotspot. Compared with traditional brine lithium extraction technology, capacitive deionization has attracted widespread attention as a result of its advantages of low energy consumption, low pollution, high recovery efficiency, and high purity. This review summarized the research progress of capacitive deionization in brine lithium extraction, including the mechanism and device design. Further discussion focuses on four lithium extraction materials clarifying the crystal structure and lithium extraction mechanism. In-depth investigation of the modification means of these materials is the core research point of this review, followed by analysis and generalization of the characteristics and modification principles of these instruments. The performance evaluation method of material lithium extraction and the comparison of properties of different materials are also listed in detail in this review. In summary, this review gives a detailed summary of latest research progress in lithium extraction by capacitive deionization, and provides an insightful outlook on the modification measures and future development direction of lithium extraction electrode.