It has been shown that if a photon is scattered by a relativistic electron in a strong magnetic field, this may cause the Raman effect due to a transition between Landau levels. We study the possibility that this quantum effect occurs in some compact objects. We find that there is a multiplet-like structure in the quasi-stellar object (QSO) 1303 + 308 spectrum, which is consistent with that expected by the Raman effect. It indicates that there might be a magnetic field strength about 5 × 106 G in the environment of this QSO at redshift 1.7175.