Multifunction radio frequency (MFRF) systems support multiple functions including radar detection, data communications and jamming. Thus, MFRF systems can obviously enhance the survivability and the effectiveness of weapon systems in complex battlefield environments, and represent an important development tendency of military equipment. This study proposed an MFRF system based on MIMO array (MIMO-MFRF), which could overcome the limitations of existing systems such as the low efficiency of supporting multiple functions etc. Analysis showed that by exploiting the spatial and waveform diversity of MIMO systems, MIMO-MFRF systems provided multiple functions simultaneously. Then all of the detection and communication performance, the capability of anti-reconnaissance and suppressing interference, and the compatibility of the MIMO-MFRF were compared with those of the conventional MFRF system, which demonstrated special superiority of the MIMO-MFRF system. Finally, the key techniques of MIMO-MFRF systems were analyzed. This study should be a refenence for developing next-generation MFRF systems.