The optical property of a Zn0.8Cd0.2Se-ZnSe strained-layer superlattice (SLS) has been investigated by making use of photoluminescence and time-resolved spectra. It is found that the donor-acceptor pair (DAP) band shifts towards lower energy with decreasing excitation density and increasing delay time. The luminescence lifetime of the DAP band is slower than that of the exciton luminescence. On the basis of these results the DAP band originates from the radiative recombination of the donor-acceptor pair in Zn0.8Cd0.2Se-ZnSe SLS.