In this paper, we have briefly reviewed the work on two-photon spectroscopy of alkali elements and its applications. The technique of Doppler-free two-photon spectroscopy is briefly summarized. A review of various techniques adopted for measuring absolute frequencies of the atomic transitions and precision measurements of isotope shifts and hyperfine structures (HFS) is presented. Some of the recent works on precision measurements of HFS constants of 6𝑠 ${}^2S_{1/2}$ level of ${}^{39}$K and ${}^{41}$K, 9𝑠 ${}^2S_{1/2}$ level and 7𝑑 ${}^2D_{3/2}$ level of 133Cs are also discussed.
