The electronic structure of CdS nanorods doped with manganese ions in the magnetic field is calculated based on the effective-mass theory, the conduction and valence subbands are found to be non-degenerate in Mn-doped CdS nanorods, the split energies of the valence subbands increase as the increment of the concentration of manganese ions. The possible transitions between the six lowest conduction subbands and the eight highest valence subbands are presented, the optical circularly polarized properties of each transition are also labelled. Through the calculation, it is found that the optical transitions can be influenced by the concentration of manganese ions and the applied magnetic field, and the radiative intensity of the transition in Mn-doped CdS nanorods increases with the increase in the manganese ions.