Provided are a multi-input multi-output system which overcomes a disadvantage that optimal receiving performance cannot be maintained according to an installation environment and a performance change of a receiver when a receiving module is configured by using a fixed attenuator and a fixed phase in a line-of-sight multi-input multi-output system configuration and analogously controls an interference removing module of a receiver including a variable attenuator and a phase shifter which are controllable to enhance a receiving performance and increase frequency efficiency, in order to maximize a signal-to-interference ratio of each path and an operating method thereof.