Lithium-selenium batteries have attracted much attention as secondary batteries due to their high energy density, high specific volumetric capacity, and moderate output voltage. However, the practical application of Li-Se batteries is hindered by the shuttle effect, poor conductivity, low active material utilization and fast capacity fading. In recent years, researchers investigated the charge-discharge mechanism of Li-Se batteries thoroughly, and studied effects on electrochemical performance from various new materials, including carbon materials and metal compounds, as cathode host, interlayer and electrolyte additives at the same time. This review systematically summarized the research progress of electrode materials, interlayer and electrolyte additives, with focus on charge-discharge mechanism and system optimization. We hope this review could provide perspective for the further development of Li-Se batteries.