Abstract: We suggest an empirical method for interpreting the 4.2.K PL spectra of certain complex defects. The essence of this method is assuming a constant k to take care of the difference in photoluminescenoe efficiency of certain coexisting defects. Some useful results have been obtained by applying this method to the interpretation of the 0.65eV and 0.80eV bands in the PL spectra of undoped, SI LEO GaAs reported in the recent literature. It is shown that the use of this method helps to shed some light on the nature of the defects involved. This success reflects the reasonableness and usefulness of the proposed method in interpreting 4.2 K PL spectra of certain semiconducting compounds, especially GaAs. In addition, the present results also support the common origin hypothesis for EL2 and the arsenic antisite AsGa as well as the strain model for EL2 proposed by one of the authors in two previous papers.