The SAC (symmetry adapted cluster)/SAC-CI (configuration interaction) general- R method is successfully applied to the photoelectron spectrum of ethylene. The theoretical spectrum satisfactorily reproduces the outer- and inner-valence regions of the spectrum. The exponential generation (EG) algorithm followed by perturbation selection (PS) is shown to be useful in the generation of small and yet effective higher-excitation operators for the SAC-CI general- R method. The peak at 23.7 eV is assigned to the `twinning' ionized states, the 2 2A g and 3 2A g states, and the peak at 27.4 eV is attributed to the 6 2A g and 7 2A g states. In the energy region around 31 eV, some ionized states are suggested to locate with small intensities. The 1 2B 2g state obtains its intensity by the initial state configuration interaction.