With the rapid expansion of the communication industry and the development of technologies, such as optical interconnection and on-chip experiments, there is a growing demand for integration and miniaturization of devices such as lasers. Semiconductor nanowire lasers have been widely studied in the field of micro/nano-lasers due to their unique one-dimensional structure and flexible bandgap control performance. Semiconductor nanowire lasers with single-mode output are of great significance in the fields of optical interconnection, sensing, spectroscopy, and interferometry. This article reviews the basic technology and research progress of single-mode semiconductor nanowire lasers. First, the common materials of semiconductor nanowire lasers are introduced, and the basic mode characteristics are analyzed using the circular dielectric waveguide model. Subsequently, the main methods and development status of semiconductor nanowires achieving single-mode laser output are elaborated. Finally, the challenges faced by each scheme are summarized.