All-solid-state single-frequency continuous-wave (CW) tunable titanium sapphire (Ti:S) lasers act as the important source in atomic physics, quantum information, Raman spectroscopy and other research fields owing to its advantages of narrow linewidth, perfect beam quality, high stability, wide wavelength tuning range of 650~1 030 nm, which can cover the transition lines of many kinds of atoms. Especially, with the development of precision measurement, quantum simulation and other new research fields in recent years, researchers have focused not only on wide tuning range, but also on conversion efficiency, output power, continuous tuning capability, stability and noise properties of titanium sapphire laser. The important research progress of all-solid-state single-frequency CW Ti:sapphire lasers in recent years are summarized.