Ince-Gaussian modes are the third complete family of exact and orthogonal solutions of the paraxial wave equation following the Hermite-Gaussian and Laguerre-Gaussian modes. Its transverse mode pattern is diversiform, and the helical Ince-Gaussian modes exist separate spiral vortex structures and carry orbital angular momentum, which makes Ince-Gaussian modes have broad prospects in the fields of particle manipulation, biomedical, optical communications and so on, and have attracted a great deal of interests. The theory of Ince- Gaussian beam is presented in the paper, the methods of generation of Ince- Gaussian mode laser are addressed, and the future development of high efficient Ince-Gaussian mode laser is disscussed.