With the heteroepitaxial GaAs layers grown on Si substrates,We have studied the excitation intensity dependence of the near- infrared photoluminescence (NIPL )related to the peak energy (77 K) at 1. 13 eV (A band) and 1.04 eV (B band) present in GaAs epitaxial layers grown by MOCVD.They can be explained by the recombination luminescence of the donor-acceptor pair.Taking the Frank-Condon shift into account,the energy expression with electron-lattice coupling effect is revised for deep donoracceptor pair. According to the experimental results, the sum of binding energies both Ea and Ed has been fitted, that is 0.300 eV and 0.401 eV, corresponding to A band and B band in NIPL spectra.