Abstract: Single-frequency all-solid-state lasers are widely used in the fields of high resolution spectroscopy, coherent communication, radars, and gravitation-wave detection and so on. Single-frequency all-solid-state laser is one of the important research fields of all-solid-state lasers. To adopt appropriate single-frequency laser technology better and meet different requirements in applications, several techniques to realize single-frequency all-solid-state lasers were summarized, such as microcavity, coupled cavity, birefringent filters, F-P etalons in cavity, unidirectional ring cavity, twisted mode cavity. Their principles and developments at home and abroad were introduced. The characteristics and application situations were also compared and summarized.