Abstract: A multiple input multiple output (MIMO) tester tests various communication parameters of a MIMO device. The MIMO tester includes a first attenuation circuit, a switch circuit, a controlling circuit, and a divider circuit. The first attenuation circuit adjusts an equivalent resistance of the MIMO tester, wherein the first attenuation circuit is electronically connected to the MIMO device. The switch circuit comprises a plurality of switch elements, wherein each switch element comprises an input end, a first output end and a second output end, wherein the switch circuit is electronically connected to the first attenuation circuit. The controlling circuit controls operation of the switch circuit, wherein the controlling circuit is electronically connected to the switch circuit. The divider circuit electronically connected to the switch circuit receives electronic signals from the MIMO device, divides each electronic signal into a plurality of sub-signals, and sends the sub-signals to at least one test device.