In order to obtain a tunable ultra-broadband absorption spectrum under transverse electric (TE) waves and a high reflectivity under transverse magnetic (TM) waves, an electromagnetic absorber is designed based on the plasma metamaterials and the lumped resistors. Its absorptivity, reflectivity, surface electric field diagram, surface current diagram and energy loss diagram are calculated by the full wave simulation method. The influences of its structural parameters and resistance on the absorptivity and reflectivity are investigated. The research results show that, by means of the excitation for different plasma resonance ranges, not only the absorption property is improved, but also the tunable absorption spectrum can be obtained. As for the designed electromagnetic absorber, not only the ultra-broadband absorption of TE waves can be realized, but also the polarization splitting of TE and TM waves can be achieved.