The interaction between light and atoms, molecules, and quantum dots in metallic micro-nano structures is a core scientific issue in the field of micro-nano optics. In recent years, scientists have made great progress in realizing surface plasmon amplification by stimulated emission of radiation and developing plasmon lasers due to the rapid development of nano-material preparation methods and nano-processing technology. We review the advances in directionality of surface plasmon amplification by stimulated emission of radiation based on metal micro-nano resonant cavities, list several kinds of resonant cavity structures which improve the directionality and elaborate on the physical mechanism. Meanwhile, we also compare the characteristics and properties of different cavity structures.