Correlated photons are generated by the spontaneous parametric down-conversion (SPDC) effects of nonlinear crystal pumped by highly intense laser. Two different quantum efficiency calibration methods of analog detectors and photon-counting regime are presented, including the theoretical expression, experimental plan, the advantages and disadvantages when compared with traditional methods. The application range and expression of the quantum efficiency of analog detectors in different calibration methods, as well as the last advances in photoelectric detectors calibration field and fundamental ideas are summarized. The next direction of investigation and the method of realization are mentioned. The future of this field is also viewed.