A Multiple Input Multiple Output (MIMO) antenna system adaptable to an environmental multiplicity is provided. A MIMO antenna system includes a first antenna element, a second antenna element, a receiver for receiving at least one of different polarized signals through the first antenna element, a channel estimator for estimating a channel using a signal received via the receiver and a signal received via the second antenna element, and a correlation comparator for controlling the receiver to receive a specific polarized signal according to a correlation calculated from the estimated channel.