The present invention relates to a method and apparatus for supporting multi-users using a massive MIMO technology in an FDD environment. A communication method of a UE in a MIMO system according to an embodiment of the present invention may comprise: estimating a channel; calculating a first precoding matrix indication having a minimum correlation with the estimated channel; and transmitting the calculated first precoding matrix indication to a BS. According to an embodiment of the present invention, in a massive MIMO system, the UE feeds not a pre-coder close to a channel thereof but a pre-coder close to a null space of a channel back to the BS, so that an IUI can be reduced even in an