Faraday laser is a novel external cavity diode laser (ECDL) that uses the Faraday anomalous dispersion optical filter as the frequency?selective element. In principle, the changes of Faraday laser output wavelength with the laser diodes' temperature and current always corresponds to the atomic transition lines. The laser frequency can be effectively locked to the atomic transition spectral line, achieving a narrow linewidth laser output signal. Both short?term and long?term frequency stability are good enough for some applications. The development process of Faraday anomalous dispersion optical filters, and the mechanism, development process and advantages of Faraday lasers are summarized in this paper since the Faraday effect was reported in 1845. Combined with the research results at home and abroad, the technical bottlenecks and corresponding solutions belonging to different stages of Faraday laser development are introduced. The important value of Faraday laser in the quantum field, especially in the field of quantum precision measurement, in the future is also anticipated.